I believe the next patch is nerfing the warlock's PvP abilities. Dots will now break Fear. However, I could be wrong. Oh god, I hope I'm wrong My main's a warlock and my favourite tactic in PvP is Deathcoil + Fear + DoT + DoT +DoT + Fear....rinse and repeat. With the possible changes, I might have to rethink a new strategy ie. hiding in bushes while slapping DoTs on every single thing that runs by.

For levelling purposes, I would recommend going Affliction until you hit level 50 before respeccing to Demonology for the Felguard (its tanking and DPS abilities make me wibble). This is just a personal preference. Maybe other warlocks could share their opinions?