My experience is that decent PA cabs are heavy enough already without putting a power amp in each of them too!
I run Mixer --> Feedback Suppressor --> Power Amp --> Passive PA tops. The first three all live in a 6U rack case, permanently wired together, so set-up at the pub is really very simple ... plug in the XLRs for the three mics, plug in the speaker leads for the two tops, game over.
I used a 4-channel power amp with bridging options down to two channels most of the time. This approach also allows me to add foldback monitors if I want them, and also means that a bass amp fail isn't a problem since I can divert one of the power amp channels to drive my bass cab.