It's great if you have a good group with you. I've got some pretty good loot doing it recently, but I haven't boughten nor provided the service. I've just done it myself with a few friends.
To do it effectively you need 3-5 people now. Killing the same person over and over no longer works. Build 100% EP and take turns killing everybody in the group. Do this for every player. You should be low EP and now you go and charge it up again. Repeat.