I played with the concept amp, and the first off one they took to NAMM last year.
Sounded real good for 30 watts. You can dial in lots of tones, but it's essentially a single channel with no footswitch, so unless you use like one setting, it would not be ideal for live performances. ALMOST loud enough to play with a drummer in practice, depends on the drummer I guess.
The 1x12 cabs are constructed like the 4x12's; all wood poplar, dovetail joints, good hardware and chrome grill, velcro pads for quick removal for mic'ing.
Lots of guys are throwing away the Eminence speaker and putting in a V-30 though, I hear it's a big improvement.
I'm trying to get an empty 1x12 cab from them without a speaker, we'll see if I can pull it off.
I don't know what the SST sounds like, they had one in the practice studio when I was A/B ing my Rev to a Chadwick, but I had no interest in it.
On the Chadwick, the clean channel was awesome, and it loves pedals, but I couldn't get the lead channel to where I was happy with it. Sounded too much like a hot-rodded Marshall.
Edit: I got to beta test the Plus series last summer. I love the new transformers and am having them put in my Rev. I'm sticking with my Rev Series One though, I don't run the loop anyway and don't need the FX boost. I personally don't care for the Marshall style rocker switches and the little red push buttons.