I like
StulleMule:
http://stulle.emule-web.de/things I like and use a lot:
Fairplay: what you just finished downloading gets a high upload priority until you share it at least 1:1
Push small/rare files
Equal Chance for Each File: if you have a good upload speed and want to push many really rare files this is it
Lovelace Credit + Fine Credit System + PBF
and the usual
Infinite queue
Slot limiter
Multiple Friendslots
Powersharing
Share only the need + Hide overshare + Selective chunk sharing
most of these are already available on MorphXT, but I like the few extra features of StulleMule
a similar client based on Xtreme is
Mephisto:
http://mephisto.emule-web.de/