Gryff

So let me get this straight, you put classes like paladin low on the list because they do little damage which makes leveling slow, but then you put stealth classes at the top because of stealth...? ???

Both are solid picks for PvE and PvP. Mages tend to outperform Warlocks early on, but Warlocks eventually start swinging back around during the later raids. As far as deciding goes, I'd look at the play styles of each and figure out which looks more enjoyable to you.