Sound is amazing. I have a Ibanez JS10th and the SATCH patch sounded just spot on. Amused to see that the Drive control goes up to 11 :). It doesn't take much to clip the unit when just adding patches, but after a half-an-hour of tweaking, you come up with an ace sound that never clips.
The Distortion is exellent for a rack unit. Having (in effect) 2 12AX7's in it, this helps remove the "bee in a can" sound. Everything is available from solidstate stack to warm vintage Jazz to really metally sounds.
More recently I have purchased a Marshall JCM2000 TSL602. The Compressor and Expander really enhance the sound and the huge eq (7 digital, 5 analog) really helps shape the sound.
In an FX loop, the delays are incredable. Tap, stereo and regen types, they are all adjustable to 1ms and can be played before or after the reverb in the chain. The Chorus and Flanger are exellent also. The tremelo and pitch-shifter are a couple of jokes but I don't use them anyway.
You really have to work hard to get this box sounding muddy and messy.
I dropped it onto concrete once and there is only a slight dent in the rack mounting point. All the components were still OK.
Can draw a bit of power though, so if you are playing an outside gig with just the band (no lights etc) perhaps check the generator specs.
I play anything from Dream Theater to U2 to more old style blues and this box aces them all. You need to get a few add-ons to really get the best out of it (even to remote pedals to change the patchs will do) but, even if I only end up using it for 1 effect, I doubt as if it will ever leave my setup. very recommended.