I like many of you have run the gamut of different amps an pickups and have never been happy with the tone they produced We also have tried just using a PA with mics and traditional monitor rigs with no luck.
After 400+ gigs here is what we do in Caravan Gypsy Swing Ensemble with no problems. We each run AKG C1000S mic into the vocal line of a Trace Elliot TA100 acoustic amp. This functions as a glorified stage monitor. We then take the pre-eq line out of the amp to the PA head. The TA100 is the perfect amp for that because it has a notch filter and a 5 band eq for the vocal line so you have a lot of control. It is an expensive rig but I just do not have feedback problems and PURE acoustic tone. I have been able to play in some pubs with thunderous crowd dins with no trouble.
Our other guitarist also did this for a while with a Fender Acoustisonic amp. It proved problematic due to the fact the fender had only 2 tone knobs for the vocal channel.
I would love to hear what luck anyone else has had with going straight acoustic.
I hope this helps!
Caravan Gypsy Swing Ensemble