which combo would lvl faster / farm better?

which would level up faster and be better at farming stuff on the way: mage/mage or lock/priest ? And why?

Mage mage would be straight forward DPS, tho you could use one as a scorch stacker and the other fireballs. Or one uses frost and the other fire so it takes ages for a mob to get there.
Lock priest would be dots and fearing, priest adding to locks DPS with the added bonus of being able to heal.

Personal preference. I'd go mage mage just for the DPS, ease of use, and cause you then get 2 sheeps, lots of aoe and much pain.

I would go with lock/lock or lock/priest.

I played 2x mages to lvl 20 or so but it was a bit of a struggle for me. I also played 2x locks to lvl 20 and it was a breeze compared to the mages. The pets give you added options. Fighting elites become a lot easier. With the 2 mages I had real problems taking down the elites in Ghostlands, with the warlocks it was cake. Maybe I just played the mages wrong but their abilities seem more movement and positioning based, ie blink, cone of cold, etc, which are not boxing friendly.

Warlocks on the other hand have pets, fears, dots (and most of your dots don't require you to face the target) which all help with killing stuff quickly and safely. You also have life tap and dark pact (if specced) to help with mana regen so almost no downtime.

Mages can solo AoE packs of mobs but the techniques are very movement based and I don't know if you would be able to pull it off boxing multiple mages.

I played 5 mages to about lvl 15, and they were pretty good, but man oh man, 5 locks is amazing. you got imps and void walkers. They are not nearly as squishy, and with 1 second cooldown/cast for your dots, you can dot up 3 critters in the time it takes you to get one cast on a critter with the mages.

mmm I just realised how much pain you could make with 5 locks.
May have to make this team next :P