I have one. I used it as my main amp for all the stuff you hear on my songs here
http://www.myspace.com/ChrisDuerringer.
I find it does a great job with those saturated Soldano and Hot Rodded Marshall sounds. I currently use my 5150 most of the time, but the MP-1 can go head-to-head with it every day of the week.
In terms of setup, my chain looked like this:
Ibanez RG -> ADA MP-1 -- [effects loop send]-> Behringer Ultra-Graph Pro->BBE
Sonic Maximizer->Lexicon MPX-200--[effects loop receive]->Fender Princeton Chorus effects loop receive.
So basically, I had all my effects in the ADA effects loop, then plugged the ADA out into the effects receive of a
Fender Princeton chorus. It would sound better with a tube power amp, but I thought it was a good tone for the money.