Being in Oklahoma, odds are I'll end up in an LDR. That's fine by me though, the possibility of moving away from here again sometime is appealing to me anyway.
The worst downside is if you get insecure. You wonder what they are doing or if they feel the same way.
The upside is it can keep you from moving too fast and you get so much time to really just talk instead of making out all the time. If you live really far apart, you get to have fun adventures meeting in between.