I was a SMN main throughout the better part of 3.x, but I dropped it like a hot log as soon as SB rolled out.

I'm still in the process of leveling my RDM, but I am enjoying it. It seems to have a relatively simple rotation that is capable of putting out pretty decent DPS numbers - which reminds me of early 3.x SMN...

So that would probably be my recommendation. If you are just looking for funsies, it shouldn't particularly matter...but at the moment BLM and SMN both seem to be in kind of a wonky spot (which will hopefully be remedied soon).