Go for Warlock. You are PvP-god.
As a Hunter you are just roadkill.
Not quite true tbh...
PvE wise, Lock and Hunter stand almost ins the same category utility.
Remember that apart from healthstones and portals, only 1 lock maybe will be assigned to land a curse due to debuff slot cap (talking about raid not just UBRS runs).
Also Lock will have to compete with the rest of cloth users for gear in all of his slots.
Hunter on the other hand is more of a support class than a true dps as it is in after TBC era.
Hunter is kinda single class use gear in terms of ranged weapons (armor also if you're alliance), but with crappy itemization.
Therefore they're almost equally needed in raids and both are under presented in the max level.
PvP wise...well that's an entirely different story.
Everything depends if we are talking about solo or group play.
I'll just state the solo play, since if you are in a premade, most likely you'll trump the enemy random team.
Warlock is more affected than Hunter in low level gear and therefore more easy to shutdown (even if specked as SL for better survivability).
Fear has his up but downs also, which might end up braking after the very first tick, also you have to take in mind WoTF (if ally) and spam dispel / cleanse / fear ward (if horde).
Hunter on the other hand is more straight forward as you're not that much affected from dispels etc but has the dead zone drawback.
Without lag and proper FD - trap macro can avoid some nasty situations.
Flare is also a nice utility safe zone against rogues + Mark can make a difference.
If you manage to get some high content gear (or craft / get the equivalent of ZG / tier 0.5 gear) you will have equally fun play with both.
Just stating that neither of both is PvP-god...
