Well I've consistently sang the praises of the Ultrasound DS4 many times in the past ...it easily offers one of the best acoustic tones, most transparent amp to my ears, that I have found in that price range. Not convinced that the DS4 will have enough wattage for you with a drummer (and I assume bassist), though. They have the 100watter which may suit you better. And Fishman's Loudbox (100w) certainly gets rave reviews, as well. But for great tone for an acoustic in a small, live venue, I have not heard any better than the Bose system. Not cheap, and in a different price strata, to be sure, but you can hear why. I like the aforementioned amps well enough, but the Bose system really is in another tonal league, IMHO.
Edward