Reason why Drain Soul is used is because as a lock, when you're DPSing usually you're at your best in a group where you have a healer, and a tank. The healer will keep your health up so life taping, *there's a spec that utilizes this with the proper inscription* you don't need to throw Drain Life in the mix. And as stated, you get a bonus when the target is below a certain percentage.
I only use Drain Life when I PvP because I don't have a healer on me, and I'll take anything I can get. Yeah I can Siphon Life everyone around me, but why not throw in an extra +health.
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[20:55] Darqflame: <3 U2 Kupo
Be Jealous
[14:24] nLoD: so it can't be all that hard can it?!
14:25] Pikko: obviously for magi it was really hard.. all the time
WoW: Retired
Uncleleo - 80 Undead Warlock Earthen Ring
Kishio - 80 Blood Elf Priest Earthen Ring
Elainebennis - 80 Blood Elf Death Knight Gul'dan
EQ2: Retired
Ishio - 80 Kerran Shadowknight - Crushbone
Ishiu - 26 Ogre Defiler - Crushbone
Ishias - 36 Conjy - Crushbone
Nerstinna - 16 Warden - Crushbone
>:3