I expect that any decent PA system will work well with BIAB live. Just need enough power and speaker for the venue, and that depends on the room. For instance the Mackie SRM's sound great at home especially with a small subwoofer which makes the real-tracks stand-up bass sound real. At the restaurant / club those smallish Mackie's still work great, but the subwoofer in that room sound boomy. I usually fly one speaker up on a stand about 4 feet then use the other from the floor behind me - so it's also a monitor.

As for guitar, I mostly play nylon string type guitars which in my opinion need "hi-fi", so with the addition of a small bit of compression and delay/reverb, I just play through the PA. An added benefit of playing through one system is easy to balance and control the overall sound, which I think is very important for restaurant gigs.

I've upgraded every year and from my experience BIAB has been rock stable for live gigs for at least 5 years.