I am having no problems with it.wow, guess I'll put a red X on my ElCap installer thumb drive and hide it for 6 months
Some things took awhile to catch up including the Chrome browser, Google Drive, Dragon for Mac, Toast and Finale (finally!) but they're all good for me now. I didn't have the AU issues except in Logic – and I don't really use Logic.
MOTU MIDI and Audio Drivers for 10.11 are still in beta but they're working for me.
The continued problems that many have with Yahoo business mail started in Mavericks. Workarounds exist.
Office 2016 still has problems but they are the same in Yosemite. Office 2008 works great but is a little slower. It's still faster than it was in OS 10.5 - 10.8 – a lot.
I have not heard of some of the problems that Bays is having except one. That one was that it wouldn't boot after a couple of days. What was really happening was that it hung up while going to sleep – drove me nuts till I found the Apple support article on the SMC. Resetting the SMC fixed it.