I have a Vox DA20 (no use for bass guitar) and it is absolutely awesome. Even on batteries (when it is limited to 1.5 watts - it does 20 on mains) it is quite loud and the range of tones really impressive. The only thing I wish it had (but it doesn't) is a footpedal to switch FX on or off or better still to switch between them.

I doubt whether the Pathfinder will give you the "rumble up the legs" effect that even the 70 watt Hartkes do, but it is likely to sound OK-ish: reviews on the internet are lukewarm but I suspect that they are being written in an electric context. If you keep the volume RIGHT down the Vox will probably be audible alongside an unplugged acoustic guitar and unmic'd singer, while remaining undistorted. Just.