I don't notice a substative difference between battery life on my 2000mA Eneloops vs my 2700mA Duracells, both from Amazon, both the same age. I've used both extensively - I wore a Fenix for marathon training (yes, running!) and ran nearly every day for 90-180 minutes, so I got to A/B test both tests repeatedly until they dimmed. In my hands, Eneloops 2000mA = Duracell 2700mA. (I was hoping the Duracells would last a lot longer but they definitely do not.)

The Eneloops also definitely deliver on charge retention - they lose about 10-15% very quickly like a regular NiMH, but after that, they hold 80-85% for months. Pretty impressive, as the regular NiMhs are nearly completely dead by then.

When I do my next battery upgrade, I'm going to go all Eneloops (or Eneloop knockoffs.)