I have never owned but always really impressed by the Tech 21 SS amps that I've demoed. Very juicy, dynamic tone.
I owned (and wish I still had) an Yamaha DG-80 amp. That thing sounded great and FELT great, but I wasn't playing out when I had it so I can't say how it really performed. Alan Holdsworth has used them so that says something. Amps that sound great at home may not pull through in a loud band.
I currently have as a back up a Crate Powerblock, which is small and light and great to bring in case of tube amp failure. That happened to me two gigs ago, my 35 watt tube amp had no sound (later found out a loose power tube was the problem), so the Crate did the job. It sounds pretty good, but lacks the punchy feel and sense of power of the tuber amp. Hard to explain, but I think tubes just have more oomph to them that translates to what you feel back at the guitar.