If I'm not mistaken, the Gibson GA-5 is an all Class A tube amp. I'm not going to get into the ugliness of trying to describe exactly what that means, but theoretically it's noticibly louder, and there is no crossover distortion. That, combined with a bit of money for the name is why the GA-5 is so much more. Apparently 15 watts in Class A is fully gigable. Can't say I've done or known anyone who has, but that's the word from Gibson.
If you're going the 5 watt route, consider you're needs. That's pretty much practice and recording only. If you're going to jam, take the step up to 30 watts.
I picked up my used Classic 30 for $300 and it's fully gigable, plays over drums, etc. I'd recommend it to anyone with the need.
Do something you love and you'll never work a day in your life...
they also have a 15 watt model, but i already have a 60 watt gigging amp(the Beringher).
Stairway to Freebird!
I've got a Pignose G40V all-tube amp, and it seems like it would be suitable for your needs. It puts out 40 fender-sounding watts, but has a gain control, so you can get it to distort without it being too loud. It also sells for around $200. Just something more for you to think about...
Class A amps aren't louder at the same power level than Class AB amps. That's one of the more enduring myths of guitardom, doubtless started by someone selling a lower powered Class A amp. Of course, they can often be overdriven well out of Class A conditions (heavy power stage distortion), and then they're putting out more power than they're rated at.
Class A amps do put out more heat for their power rating, being the least efficient class of operation.
An overdriven, distorting single ended amp does make a different sound than an overdriven push-pull amp, with a big even harmonic content. Push-pull stages put out nearly all odd harmonics.
"A cheerful heart is good medicine."
