I use a Les Paul with Seymour Duncan SH-1 '59 low output pickups, and a Charvel strat copy. This thing is completely silent with the effects bypassed, but if you are sitting right beside it, with a thin patch cord, and the effects all the way up, you can hear the effect (phaser for example). This noise goes down when you move away but isn't completely silent. There is also some fan noise but if you think it will affect your stage noise, it is so little that no one will be able to hear it.
The sound variety is FANTASTIC. 8 amp channels gives you blackface, bassman, ac15, ac30, jmp, JCM800, soldano, and boutique cleans and overdrive. They are all great, distinct amp models. They all do a really respectable job in modelling each amp. I'm not exactly sure how the 12AX7 helps create a better sound, but whatever it's doing, it works very well. My favourite tones are AC30 and the JCM800. AC30 model is ballsy and crisp with tons of high end. JCM800 is tight with killer distortion. I felt the cleans were slightly heavy on the bass though.
The effects are good. From compressors, delays, reverbs, univibes, tremelo, flanger, again a wide variety of stuff to play around with to get your sound.
This thing has enough power to do full volume cleans, and good enough to sound like real tube distortion and overdrive - especially combined with the power output knob, it gives you a bunch of tones at usable volumes, both in your bedroom and on stage at a gig. It has plenty of power for a bar or a venue.
Don't know yet...
Absolutely the best value amp for your money. These days, something that will sound this good is going to cost you more. Vox really has made a fantastic affordable line of amps cheap enough for beginners, and good enough for pros. I think that this Vox is a better value than every competition amp out there - Roland Cube 60, Peavey Classic 30, PV Delta Blues, and has some gadgets that other amps don't have, or just don't recreate as well. If you are looking for a 400-600 dollar amp, the Vox AD50VT the best thing you can possibly get.