I have both (5 man teams). Both have pets that can tank. Both have ways to heal your pets. Both are pretty fun. Both can fight on the move (instant casts/attacks).
Some differences.
Locks lost the get the shard back ability in BG's, so if you throw your pets at people and you run away, hunters win 100% (whistle and bam, full healed pet), while locks have 10 sec downtime and down a shard.
Hunters have pets that can do pretty good DPS (as BM) and still tank. Locks have specific pets for specific situations (until lvl 51 with felguard). Hunters also have a wide variety of pets that you might like (either skins, abilities, talents, etc).
Locks kinda lose on the CC part. Fear is too dangerous to do reliably. Sure they have seduce, but they lose a pet in the process, where hunters can trap and have the pet also.
Locks lose in tanking (until you get part down in affliction tree). Mail beats cloth if a mob wants to beat on you. Also hunters can feign to get the mob back on the pet.
I would try both, can't hurt. By lvl 20-40 you can see a difference and then you can decide then. Hunters are probably easier, but locks are probably for people that want them really bad, so they will find ways to make them work.
Good luck.