I started out playing classical with my fingertips because I was at the time primarily a bassist, which I cannot play with nails. When I decided to just stick with guitar, I grew out my nails. I'm finding that it gives me control that I could never have with just my fingers, and a tonal quality that I am quite proud of.

Just after Christmas, though, I cracked my thumb nail and took a big chunk out of my middle nail while at work (my middle nail has a weak spot, and I hit it just right on a credit card reader), so I decided to just trim everything down and grow them out evenly. I pretty much stopped playing classical until they grew out enough to do something with. I can't stand playing with my fingertips anymore. My nails are still short now, and it's driving me crazy.

The only downsides that I've found are that you can't play bass guitar, and the maintenance on the nails can become rather annoying at times. And my fiancée absolutely despises them.