The XP in PoD has been great at 55. Getting 1% per kill on rats, or 2 flies.
Avoid the spiders and diseased Malarians - insta smack on those :(
The bugs etc will regen up to 40% (I've had em jump to 50%) if you get out of melee range when they're below 20% HP.
Easiest I've found is to twist in Chains (23) or Binding (51) at 22%, and at about 18% (on a single) you can just stand there, melee a bit if ya want, till dead.
Chains (23) doesn't always take, but had no prob with Binding (51). I also haven't had much luck with the AE snare Strane (54). Too iffy if you're quading, least as I've seen.