• Overall Impression: I'm VERY happy with this upgrade of OSX. I cannot explain WHY it's working better, but I had a hunch this was going to happen. It's as if I upgraded OSX to Snow Leopard and got DP7 in a package deal! It fixes many things, or at least brings them back to their former state of workaround in which they could be made to work if you knew how. 6.02 and Leopard really were having a cat-fight, if you ask me, and DP was getting clawed to pieces. Now they've made up and are all curled up and purring. Honestly, I haven't been this excited and pleased to work in DP since OS9 and DP 2.73, back in about 2000. Ok, let's get on to some specifics.
Loading VI's
My early tests were all done in a file with only one VI: Ivory. Now I've done some more complicated things, and the news is good. So far only up to 6 instruments performing, but there were over 20 loaded, plus I opened Mach Five 2 to play with it for a while, all while in the same file, and despite doing a lot of "messing around" in Mach Five 2, DP never flinched. I was able to run Kontakt 2 Player and Wallander Instruments' WIVI in virtual mode (non-real-time) for the first time without artifacts. Further, I was able to bounce the VI's to disk (from the V-Rack, no less) without the intermediary step of "freezing" the tracks. The exception to that was MOTU Symphonic Instrument, which I first had to record to a track. I assume that Mach Five 2 would be the same way, along with Ethno and other MOTU packages.
So, my first try at bouncing to disk was with an oldie of mine from 2008 - Sextuor Mystique by Villa-Lobos. It's a sextet for sax, flute, oboe, harp, celeste, and guitar. I decided to try going direct to disk without freezing. It worked for NI's Kontakt 2 Player and WIVI, but the instruments that were on MSI were simply missing. So, I froze those tracks and tried it again, this time with 2 recorded tracks and 4 tracks in "non real-time" mode.
Sextuor Mystique.mp3
As you can hear, there are no artifacts. This is not mixed or automated, by the way, being just the raw tracks pretty much as I played them on the WX5, so don't expect a perfectly balanced recording. I wish I could blame that on Snow Leopard, but it's just because I couldn't find the file that was more complete. This is a backup file that survived the big crash in February. Strictly raw playing for illustrating the point that it's working (along with bounce to disk without freezing).
•Stand-Alone VI's
• Some people have said that MSI or MachFive2 are not working for them, or at least I THINK that's what they said. I had zero problems with them as plugins, other than the fact that they still won't bounce to disk without the intermediary "freeze" beforehand, and they won't operate in pre-buffered (non-realtime) mode. [Isn't that ironic?] Of course, I was using them as plugins. What many have been talking about, however are the Stand Alone versions of MSI and M5.2. These work in StandAlone Mode if you remove the AU component from the /Library/Audio/Plugins/Components folder. Drag it to the Components (Disabled) folder. [edited 9/6/2009]
• MOTU Symphonic Instrument Standalone Mode: Works fine if you disable the AU component as described above. [edited 9/6/2009]
• Ivory Stand-Alone: Works perfectly as far as I can tell.
• Akoustik Piano Stand-Alone: Works perfectly as far as I can tell. I didn't try the self-record feature, but it gave me no reason to doubt that it's working as it should.
• Native Instruments' Kontakt2 Player Stand-Alone: Crashed the first time I loaded the Solo Stradivari instrument, but stayed up when I loaded anything else. After loading other instruments, I was able to load the Stradivari Solo Violin, too. Go figure. I was able to load and play lots of instruments, but if I wanted to disable one by clicking on the "x" button, it would crash every time. Otherwise, it seemed to be stable enough to create Multi's and other messing around.
• Vienna Symphonic Library Stand-Alone: Works perfectly and beautifully. Wonderful interface and beautiful instrument sounds.
•MOTU's Clockworks Software for MIDI Time Piece, etc.: This was the first app that caused me to have to install Rosetta. A dialog came up asking if I wanted to install Rosetta. I clicked OK, and it found the installer and installed it with no more input from me. Clockworks loaded fine, and communicated with the MIDI Time Piece AV without any issues.
• Audio interfaces are all working (PCI 424e and Firewire), as well as their Setup apps.
• PCIe-424 Audio Installer (and Universal audio Installer): If you used the installer, you may be surprised to find that your interfaces won't work. That's because the installer adds a file that must NOT be there for it to work. Go to HD/SYSTEM/LIBRARY/EXTENSIONS and look for MotuTigerDriver.kext, then throw it in the trash. (don't do this unless you're using Snow Leopard! Maybe Leopard, too; I don't remember. Obviously, you need it for Tiger, but if you're using Snow Leopard, your Tiger days are long past. Anyway, after throwing out that file, restart your Mac and your PCIe 424 card will link up fine with the audio interfaces.
• MOTU PCI CueMix: Works fine.
• Apple's Audio/MIDI Setup has changed. I haven't examined it carefully, so I can't comment much except to say that it looks a lot different, and selecting audio interfaces for setup is much less confusing now.
• I did not update my iLok files for fear of rocking the boat and having to pay Waves about $400 for the privilege of re-authorizing my plugins via WUP. I know it's very unlikely that the iLok updaters would cause any problems of that nature, but i'm not going to do it if it doesn't make me. It appears that everything is working. I've opened almost everything that's on iLok, and it all works.
• In other posts, I mentioned that Spaces is working for me again. DP 6.02 and/or some version of Leopard broke the relationship they had going together, but that is now back and very stable. Plus, the floating Control Panel will follow you to each "Space" so that you're never without it. If you want to know more about what I'm talking about, check This Post in the Tips Sheet for the full story. Of course, that could get broken again, but as long as it's there, I'm going to enjoy it. That is a great way to work.
• Some have commented that the colors in DP seem deeper and richer since the SL upgrade. That's because the Monitors control panel defaults to a factory setting and needs calibrating. All your graphics will be substantially more contrasty until you do the calibration. For some reason, many of my older calibrations were no longer present.
• I've posted elsewhere on the "Return of the Tap Tempo Workaround." Either Leopard or DP 6 (I forget which) busted Tap Tempo so badly that even the old workaround wouldn't save it. Now the workaround works around again. Though I've posted it elsewhere, I'm going to add that information at the bottom of this post so it gets seen by more people. Everyone needs Tap Tempo!
• Quickscribe: Here's an interesting phenomenon:

I have the Quickscribe fonts installed, as well as Opus and other notation fonts. What's it looking for, anyway? Notation works fine in the Notation Editor:

•CPU Meter ("Audio Performance" Meter): I think the picture is pretty self explanatory. The green meter (showing 4 CPU's) is from Activity Monitor, floating directly over DP's Audio Performance Meter. It appears to be well into the red, and yet all is ok with the Mac's CPUs. The mystery continues.

• Continuous Data Reshape Tool is working properly again, at least one aspect of it, that is. When doing a percentage drag over selected CC data or pitch bend, it was doing a proportional shrinking not worth describing here, but now it is doing what it's supposed to do. Just be sure to use QuickFilter even if you've got the panel set for Pitch Bend-only. Otherwise, it will operate on hidden data. That's a bug, but it's been there a long time.
These next two are not necessarily related to Snow Leopard:
• Conductor Track Tempo Markers: Dragging tempo markers below the last tempo, in the shaded area, makes them invisible. You can't see what you're dragging or where you are putting it until you release the mouse. That' s a hard way to work. The Tempo Markers need to be visible while dragging them, no matter where you drag them in the window.
• Audible Mode with VI's: [edit: I had posted a mistaken assumption here, but I've removed it to avoid confusion. No change in DP's functionality here. Shooshie's functionality? Very possibly some new bugs there.

Speaking of V-Racks, I have not opened Plogue Bidule yet. That's kind of involved, so I'll save that for another day. Maybe someone else already has a template running in Snow Leopard.
There's probably more, but I'm going to post this and get on with my life. Below is the stuff about Tap Tempo.
Good night and Good Luck,
Shooshie
•Tap Tempo: First of all, the music and the cursor (wiper) are literally dissociated. The wiper is moving correctly with the tap. The music does not; instead it follows the existing Conductor Track, or the 120 BPM default if there is no existing Conductor Track. This means that the music is always playing at the tempo of the last pre-recorded tempo marker it passes. Thus, at all times the pre-existing tempo markers govern the fastest tempo for the music (but not for the cursor). Even though you may be tapping faster than the marked tempos, and even though the cursor is correctly following your tapping, the music cannot exceed speed of the last passed tempo marker.
Now, what THAT causes is for the cursor to get far ahead of the music. If the music finally DOES pass a tempo marker that is faster then the tap, the music will try to catch up to the cursor in a flurry of notes. Once the music catches up, it will follow the tap-tempo until it passes another pre-existing tempo marker that is slower than the current tap. Then the dissociation begins again, and the cycle repeats until there is another section where the pre-existing tempos are faster than the tapped tempos, and the flurry of notes happens again as it catches up again. If it never passes a pre-existing tempo marker that is faster than the tap, the music will not catch up to the tapped tempo until well after you have stopped the song.
Try it. You can tap with "MIDI Keys" [COMMAND-SHIFT-K], so you don't even need your MIDI keyboard to try this:
1) Just open the DP Preferences Window and go to the the "Receive Sync" preferences.
2) Set the receive sync prefs for Tap Tempo.
3) Open MIDI Keys [COMMAND-SHIFT-K]
4) Set the tap for your choice of keys on the MIDI Keys keyboard, set the number of count-off beats, and so forth.
5) Be sure you are in Conductor Track Mode.
6) Engage Receive Sync [COMMAND-7]
7) Record enable the Conductor Track (be sure nothing else is record enabled, or you might erase data)

9) Start tapping. After your count-off beats, the music will begin.
Now, Tap in time with the music at first. Then speed up as fast as you wish. After a few bars of sped-up taps, notice that the wiper has followed you, but the music is way off behind you (assuming you tapped faster than the existing or default tempos). So, at this point, slow WAAAAYYYYY down. Keep tapping slowly, but wait for the music to catch up with you. After it does, you may "conduct" the music by tapping slowly, but once you exceed the existing tempos again, the wiper and the music will dissociate as before.
THEREFORE, This implies a work-around:
1) Set only one preexisting tempo.
2) Set it at the beginning of the song, or at your current starting point if you do a 2nd take later on.
3) Set it for 400 bpm.
4) Erase all other tempos that come after it. (Tap Tempo won't work if you skip this step)
5) Then do the Tap Tempo. It should follow the tap, since the last pre-existing tempo it passed was as fast as DP can go.
The rule still applies to the workaround (if you exceed the existing tempo, the music will dissociate), but since 400 bpm is the maximum allowable tempo, you can't exceed that, anyway.
Yes, it's inexcusable that this Tap Tempo mess has been around since DP 4.0 That's over 6 years now that one of the most important features for composers and arrangers has been broken. But at least it's back to "workable" after a total hiatus since DP 6.
G'nite again,
Shooshie