In terms of exp gain, FATEs are the way to go pre-50. They're just close and convenient. The prominence of FATE parties rose for a reason, especially in the early days of both launches. Of course, FATEs is soul killing, mind-numbing work and forces you to spend more gil on repairs than it rewards, but it's fast.

Although it's slow, I prefer doing hunting logs, leves, and careful planning of my challenge logs while waiting for a dungeon or dutyfinder to open up as a dps. I'll do FATEs occaissionally, but I can't stomach the things for more than 10 minutes.