Take Parker's advice for what it is worth - free.

I use a spinning reel when I am boondogging, casting Dick Nites, or need to cast really light weight terminal tackle for picky fish.

All else, I use a baitcaster. That'd be for drift fishing, big spinners, spoons, jigs, hover fishing, backbouncing, trolling, mooching, plugging, jigging.

Note: Most of the true, die-hard jig guys use spinning reels. I'm not a die-hard jig guy, so ignore the baitcasting bit and jigs.

Both reels have their functionality and their place. It really all comes down the the type of fishing you do.