Crusader has a one-ppm (proc. per-minute) internal-cool-down, while Lifestealing has no cool-down whatsoever . In terms of survivability, Lifestealing is the way to go, but if you want to do some high-burst damage I would recommend Crusader, even though it isn't reliable. Crusader is solely based on luck; you can go over a minute without it proc'ing, and when it does
eventually proc. you'll have to wait another minute for it to have the chance to activate again.
Decided which would be more effective for
your play-style; luckily, if you don't like the one you pick you can always go visit an enchanter and have it changed!
Happy hunting
,
-Natlieportmn, 19 Rogue