Eneloops are low discharge batteries and if left unused will have more power in them after 6 months then will Powerex batteries. However, if both are used immediately or shortly after charging Powerex 2500/2700NIMH would last longer since they have more power to start with.

I have both batteries and mainly use Powerex in my D300 grip & SB-900 flash. I also have a battery tester and test the extra batteries I take with me. If I didn.t do any charging before leaving I will always take at least 1 set of eneloops because they loose less charge just sitting around.

Normally, I use the eneloops for weather radios, LED flashlights & small lanterns that sit for long times between use & charge.