I think it's the best automobile practice amp made, for sure! I head out an hour early to get to construction sites and beat the Minneapolis/St Paul rushhour in the morning. Batteries last for weeks/months, even when played every day.
These do sound great through a PA, and will work live. Some wouldn't even consider it, but look at all the coverband guitarists that use the Boss/Roland multi-effects systems directly into PA's on the weekends. I know 3, and did it myself a few years ago when the GT-6 first came out. The Cubes have the same COSM modeling circuitry. So think of the Cubes as a
condensed version of one of these, but with a speaker!
I've never tried the Vox variant, but they look equally promising.