I currently own and use a Carvin AG100D acoustic guitar amp. Carvin is a US company that is mail-order only (except for a couple of stores in southern California). The amp is solid state, 100 watts RMS, with three channels (one of which accepts an XLR as well as standard 1/4-inch phone plug), and onboard digital effects (reverb, chorus, flange, echo) adjustable on all three channels. Single 12-inch speaker and an adjustable tweeter.

So how's it sound? Not great, but that's true of most of the "acoustic guitar" amps I've tried. There's marketing hype, and then there's reality, I guess. I bought this amp based on a glowing review, a decent company reputation, and the fact that it had most of the features I wanted. Can't say I'm terribly impressed with the thing, but I only use it as an on-stage monitor -- my "out-front" sound comes from the PA (Mackie board, QSR power amps, JBL mains).

I hear good things about the Fender SFX series, which has a second speaker in a separate portion of the cabinet facing sideways -- it's intended to simulate a stereo setup, while retaining the all-in-one combo amp configuration. The reviews say it really does the trick, but of course the reviews for the amp I currently have were pretty good also.