I've been using a Fishman Solo Amp for my performances. I place it to my side and a bit behind me. It's pretty feedback resistant. Great carry-in and setup time, and it sounds great, too. Not a ton of thump (you'd need the Bose L1 plus sub for that), but it really gets the job done for me. I almost never miss a count-in as I'm hearing what the audience hears.

My $.02.