is pvp a good way to level up ?

No.

PvP matches take 10 minutes each and give EXP depending on how good you do. If you do bad, you get cruddy exp. While in training, there is no luck factor involved (unless you count KSing, then ok. You could just move maps or something, who gives a damn.) so it's generally faster.

That is, assuming that PvP is based on luck and luck only.