All I can say is...WOW! I have never been so impressed in an amp for the price I paid for it ($375).
The clean channel sounds as good as a Fender when dialed in correctly. PLENTY of headroom, but can get slightly crunch when turned up enough (and hurt your ears in the process). With the bridge pickup (Gibson 500T), it sounds almost like a strat. With the neck pickup (Gibson 496R), it gives an EXTREMELY mellow, warm tone. I've read all of the raving reviews about the crunch but that clean channel is very underrated! The reverb...unbelievable. MUCH better than any reverb I've ever experienced (except for a few Fenders, which it would be able to hang with).
The crunch channel is where it's at. It sounds almost exactly like a Marshall JCM, and it absolutely nailed the sound I was looking for when I was finally able to dial it in the way I wanted to.
The ultra channel is PURE METAL BRUTALITY. I don't use it a lot since I'm not a real metalhead, but it would work for anyone looking for a Mesa-like sound.
There's also the "Fat" switches that add to the versatility of this amazing amp.
The amp does have an effects loop, with send and return volume knobs that can also be used as a volume boost for choruses and solos.
The Presence and Resonance controls are very effective as well. In face, all of the knobs are very touch-sensative.
Overall, this is the best amp I have ever played, and will cover any musical style. If want to look for this amp though, look for a Peavey XXX II. It's exactly the same thing with a different name since Joe Satriani left Peavey for Marshall.
You can also switch between EL34's and 6L6's for the power tubes to help you even more when it comes to looking for your tone. If it isn't in there, you either need to get a new guitar or it doesn't exist.
Also, this actually sounds good at bedroom volumes, for all of those naysayers that say that tube amps can't do that.
Oh, and did I mention that it was made in the good old USA?
I'm still stoked.