The ES100's are super sensitive so may not require much power to sound good.
I say you give everything a shot. I own a Pioneer VSX-1122K and it sounds great with my PSB speakers. I can't comment on how it would sound with your JBL.
I've also heard a Denon X2000 paired with a Jamo S608 and the sound was very good.
JBL sound is usually bright so you need to look for a laid back receiver which my Pioneer is.
Though Cambridge receivers are expensive, I think they will be a better match than anything else out there.
