AGAINST:

An instrument miked through even a reasonably good mic sounds better than most pickups, even the expensive ones. The pickups all make the guitar sound like a cardboard guitar at best, and like an angry duck at worst.

You have better control over your volume with a mic on a stand, if you play standing, because you can move toward the mic or away from it when you go from lead to backup or vice versa.

FOR:

You can get more volume more easily with a pickup, and the sound cuts through crowd noise better.

You don't have to think about not moving while you play, so you keep the instrument lined up with the mic.

VERDICT:

Get the pickup. Then use it only in noisy venues, where really good sound quality wouldn't be noticed anyway; and mic the instrument whenever it's practicable to.

All my personal (not humble) opinion, obviously.

Peter.