I loved leveling my monk, but for some reason after hitting 90 it wasn't the same. I suspect it has something to do with the switch from primarily solo play to more group play. Since shaman has the ability to do both melee and ranged specs, I'm hoping the jump at 90 isn't so extreme.

I suspect both specs are fine for leveling - it depends on which heirloom gear you have (assuming you have any). I went with enh gear, and have no problems so far. It isn't quite as face-roll as something like hunter or lock, but certainly not slow.