One thing I'm a stickler on, regardless of source, is mics. There are certain microphones I despise (such as the AKG D112, which I owned and used for many years). So when I look at drum sample libraries, the most interesting spec to me usually is not the number of layers but the mics.
I read through the BFD and BFD2 specs this past weekend, as well as the expansion packs, and was quite pleased with the mic choices -- especially compared to the expansion packs that I sold (not the Platinum Samples ones -- those are excellent, but I decided I don't have a use for Producer Packs at this point in time). It wasn't too surprising to me when I read the mic specs for the XFL and Deluxe packs, which I sold.
I'm one of those anti-conservatives in the music business. We're quite a rare breed. I hate P-Basses, SM57's, SM58's, D112's, and quite a few of the other "Sacred Cows" in the business that many say you HAVE to use if you want to be taken seriously or want good results from a session. I think the majority of people saying this are in a very narrow genre of music (most people haven't heard enough to realise how narrow their world is

There are a couple of those in the BFD sessions, but they're used in roles where they do not offend me, as opposed to general-purpose mics. Even the D112 is used, but outside the kick as opposed to inside the kick. And I've even found that auditioning kit pieces has given me a better idea of what mics I want to buy and/or use (some of them I already own) for my acoustic drum sessions.

The funny thing is, a lot of the mics I picked up in the past two years, many of them meant for close-miking a kit (which I couldn't do before), are quite cheap (under $300 apiece). It's most a good pair of omni condensor overheads that add up to a lot of dough, as well as ribbon mics.
But there are different sounds out there for sure. Many swear by Audix, and I listened to Brad's samples and found them impressive mics for the money, but not the sound I personally want. Having said that, and being familiar with their sound, I feel that I have a good idea of when to recommend them to others. They just seem a bit boxy and coloured to me -- but this is exactly what many people are looking for (especially in more recent pop music). There's nothing wrong with it, but it helps to know what one is looking for.
I'm still not quite clear on whether there is any real advice being sought here in terms of budgeting pre-amps vs. mics vs. studio time vs. sample libraries etc. So I'm just rambling based on some thoughts that have congealed after giving a few days rest from reading the postings here and noting the divergent points of view.