Re: can you help recommend a PA for my band?
Get the biggest speaker you're willing to cart around. The bigger the speaker, the better the lower frequencies sound. If you get a 12" speaker or larger (and I wouldn't get anything smaller for mains), get 2-way cabinets, which is a speaker and a horn. Even just vocals and acoustic guitar will sound tinny through a 10" or smaller speaker, unless you go for one of those Bose towers.
I'm on the powered mixer boat, but that's because I got a great deal on a used powered mixer and passive speakers. It works great, and the speakers themselves are a lot lighter than powered speakers, if you're considering cartage as a major factor.