stevec
They're sounding (and looking) good so far on my end. Nice variety and good choice of controls. I did have one weird case where I inserted the Jazz amp after trying the other Clean variations and had some static-y noise that wouldn't go away until I stopped/started the audio engine. But that didn't happen again.
That's one of the problems. The other is you insert the amp and it sounds like crap, with high frequencies that won't quit. It seems closing SONAR, re-opening, then re-inserting the effect can provide a workaround in some cases. I'll try your audio engine trick if it happens again.
I highly recommend NOT using the amps for serious projects yet because there may be some differences in the sound when the final ones arrive. For example one effect loads with different control settings than what I programmed.
Anyhow.. they all sound good here. Hard to tell whether they'll wind up as replacements for GR5 or Revalver 4, but I can already tell I'll be using delivered FX Chains more than ever before. So if this is an example of the "content" referred to as part of the new Membership program, then count me in! 
Part of the goal is to make these amps "drag and drop" so you get close to the sound you want within seconds, and then maybe you do a few tweaks. Remember, these are designed to complement what's out there, not replace the "photo-realistic" sims of individual amps...no need to re-invent the wheel. That said, I don't use other amp sims any more.
And yes, this is
absolutely representative of the type of content you'll be receiving. The Amps and Anderton Collection are the start, not the end, nor am I the only person working on these kinds of things. I came up with a new genre of effects for SONAR that I figured would be in X4, but the Cakewalk guys took one look and said "whoa...we could take this concept in an even better direction," which they're in the process of doing. It looks like they'll be done in March or maybe April.