Toontrack Superior is, well, Superior!
I started with "Drumkit from Hell " a long time ago, in GigaStudio I think. It was very expressive, but somewhat limited in terms of range of application. Which was ok, since they never claimed it was a one-size-fits-all library.
I bought Superior Drummer V1 expecting the same expressiveness, which it has, and the same limits, which it did not have! I still use the kits from V1, they cover a remarkably wide range of sounds. I confess I found the user interface to be a little frustrating, and it did hog resources, but it was worth it.
Then I upgraded to Superior V2 - the Avatar kit is expressive, as I've come to expect. But it doesn't cover as much sonic turf as V1, which turned out to be OK since I could still use the V1 sounds. I really didn't think I needed expansion kits.
Oops - I was wrong! The Custom & Vintage SDX gives me a significantly larger palette to work with. Same expressive range, just more drums! Now my biggest problem is sometimes I spend too much time auditioning drums - there are worse problems to have.
Installation was smooth, and not too terribly time consuming. If you want that many sample you do have to suffer through copying them to your computer. I'm glad that doesn't happen every week though!
Oh, and the V2 interface is much easier to use, and it is either gentler on resources, or DAWs have become so powerful that it isn't a problem any longer?
I don't use their MIDI loops often, but I did play around a little bit with the content in Custom & Vintage, and it is a lot of fun... if you are able to work with loops you'll likely find lots of useful stuff.
Superior remains my go-to drum library, and now it's even better!