I'm level 50 full affliction at Kalecos
I'd say Affliction is good for PvE, and not lose that much hp and mana as much as destruction. Affliction is good, however, i'm going to choose destruction(re-specing) for 35g.... that's how much destruction is good. it has more pros than affliction. But the downfall is that it ll eat up many mana.
It's your character, It's your decision.
I'd put in these orders: Destruction->Affliction->Demonology
Best to not-so-good-as-other
  anyway..have fun choosing ur talents.

p.s) If anyone is in Kalecos(alliance), pst me if need any help. (ReaperEater)

I'm a 68 Affliction Lock and can still hold my own with 70 Destruction Locks. They may kill me but they will die doing it. If I get first DC or Fear I own them period. At 70, I magine I'll wipe them and still live tell about and not have to watch from my ghost as I sometimes do now...