which class to play (mage or lock)

hi all
i want to creat a new chracter dps on wowtlk and i cant decide which to play mage or warlock
i will play mainly pve
what is the pros for each class ?

warlock:
pros
-less played (you will never hear a leader say "sorry full on locks")
-you can make summon stones
-everyone wants a demo lock in their raids

cons:
-usually does a bit less dps than a mage (inb4 "i can outdps all mages on my guild")
-you might be forced to play demo in raids (the reason i dont have a lock tbh)

Mage:
I play a mage and the only real pros i see are being able to make portals and having a easier time surviving if you pull mobs from the tank in instances

Both are bad choices I would say.