Most people remember the Real Tube pedals, but not nearly as many remember the amps. The clean is great but the dirty channel sounds utterly fantastic. I saw an extension cab on Craigslist and may build myself a backup stack rig.
I have a rack version of this with the 3 channel preamp and a 60 watt a side power amp. The third channel where the drive is cascaded through the clean is even better than the regular drive channel. I have it with a rocktron voodu valve effects unit and a midi control board for all the channels and effects in a rack. For being old it still sounds great.