I like it on. It can get a bit annoying, and of course Dretch FF must be off (As a tyrant/goon there are too many of the little buggers to avoid). But besides that, it keeps you in check, and adds a layer of difficulty to the game, which makes it more fun to me. If trem was a game where everyone got 400 kills in a game, it wouldn't be any fun after a while. Since it's such a balanced game, it's very successful.
Also, response to HamStar. You just gave me the idea that maybe cred payback should be based on the HP of the person you killed, or the amount of damage you did to the person. If you think about it, if you buy a $25,000 car, and over time it's value depreciates to $5,000 and you get it in a wreck and it's not your fault, are you going to charge the guy for the $25,000 you bought the car for or the $5,000 it's worth. In trem it's pretty much the same idea. If you go and run around with a luci and run back to base with 0 ammo and 10 HP, you're not as useful as someone running out of base with full ammo and 100 HP. Sorry to make it sound crude, but you're honestly not worth as much to your team as the guy who is running out is, at that point. Not overall.