Rend is a maybe. 9% health from damage might be too low but I have to TEST it first. I never just assume something will work or not work in games. Always test it. I like rend because you can just apply it and focus on movement rather than attack. Hit, run 3 seconds, hit, run 3 seconds. That will be my strategy and test phase.
In a group, you give your party many buffs. The runes can be changed on the fly so if things are too easy, Ill just switch to a treasure find build.