For what it's worth, I've done 20 in 3 hours a bunch of times, including with characters that aren't in any way optimal for any part of powerlevelling 1-20. E.g., air major shifter.

I don't usually want to level that fast. The game doesn't start at hero for me and I'd rather take longer, get to roleplay more, get into twenty PK fights by twenty or whatever, etc... but if all you want to do is speed through those levels for whatever reason, it's not that hard.

I can't honestly see hitting level 30 in 2 hours, but level 30 in 10 hours if all you wanted to do was level, is not hard.