Re: can you help recommend a PA for my band?
I'd go with powered speakers simply because you know the speakers can handle the wattage that the amps put out, you've got a separate amp per driver so they're more efficient, and there's less to carry around. Plus you can daisy-chain extra speakers or bass bins almost indefinitely and not need to buy a new amp because they're built in to each one. Then there's stuff like the built in safety cutout if they get too hot...there are so many advantages.
+1 on the Mackie SRM450s, I've worked with them for a long time and they are perfectly adequate. Each speaker is 450 watts, so two of those would be more than enough for a small venue and they sound very good, plenty of low-end reproduction for vocals and acoustic guitar.