Sublingual > Oral IMO. I'm suprised no one has mentioned sublingual.
It does somewhat depend on the specific compound though, and there are some 2c-*s that just dont agree with me regardless of how I take them(most of the halogenated ones)
I dont enjoy insufflating 2c-*s, the pain is quite intense. I would consider doing it again but only if I was trying to ration my doses better and make what little amount I had last longer.
Overall, 2c-e is the best IMO.