I own a roland Cube 60 as my main amp. I've done a bunch of gigs with it, so it's cool there. It's tiny, for a 112. Thats probly the best thing about the amp. As for reliability, i would say it beats the other two by miles. The other two (from what ive seen at GC and such) are kinda bulky and clumsy.
The best models are the Brit Combo (AC30), Metal (5150), and Blackface (Fender Twin). I use the brit combo for everything, and an overdrive when i need more balls.
I wouldnt consider buying one of these amps for their tube like tone at all. They're best for being good solid reliable amps that you dont have to worry about blowing up, and getting decent tone while doing so.
I would love to get a small tube amp, but for the reasons listed above, i dont want to. Plus being a college student, it's nice to be able to bring your amp with you, and not worry about it getting damaged while consuming mass quantities.
considering my expierence with the cube, and its tiny size and gigable-ness (nice word eh?), id say pick one up.