The Superior libraries are indeed superior to the EZD stuff. Although as far as I recall, some of the EZDs are from the same recorded libraries as Superior counterparts, just they're stripped down, 16-bit, and somewhat pre-processed. It's not like they're rubbish, just that it's a) not supposed to be their flagship product, and b) aimed at a different kind of user.
If you want the best sound and the best control over the sound, Superior is the way to go. Aside from the sounds being better, the software is more flexible, with full mixer, routing, FX, bleed, etc. control.
If you want something that's more aimed at being able to just get in there, load up a kit, drag in some grooves, etc., then that's where EZD comes in. If you're sequencing from scratch and not using pre-made MIDI grooves and whatnot, you're basically left with the "benefit" of pre-processed sounds that you can just drop into the mix and go. For me that's not a benefit, and I'd take the flexibility of the sounds and software of S2.0 any day. It might take me a bit of time to put together a kit and get all the sounds right, but it's all part of the writing/recording/mixing process. And once I have a kit I like, I save it as a user preset. Start a new project, pick one of my kits, the whole kit with all its mixer settings is loaded up. Between layering kit components (i.e. stacking 3 snares to get your 1 sound), the capabilities of the mixer, the built in FX, all the various mic channel options (from memory I think Metal Foundry gives like 4 or 5 mic channels just for the snare), etc., there are a LOT of options to play with. That said, the fact that you can so easily cheat your way around real-life drum recording/mixing problems is pretty handy. Want a big roomy sound for everything but the kick drum? Piece of cake.
That said, the stock Avatar kit that comes with S2.0 isn't particularly raw sounding. It's still fairly flexible and you can get plenty out of it, but since I added a few SDXs, I don't think I've used Avatar for anything. Maybe I've layered an Avatar snare in with another kit or something.