Mike-How is the recovery time with them? Are they as good as the ULD Eneloops for that?
I've never used actual Eneloops. I've used Alkaline and several brands of NiMH.
The old Energizers/Duracells (& some other brands that I have) work well, as long as you charge them up before the wedding. I'm likely going to do this anyway, so it was never an issue that they will self discharge. I looked at the Eneloops, but they had a lower capacity and cost more. Sure, the Ultra Low Discharge is great, but for a wedding photographer's flash, you're going to want them fully charged anyway. But for things like remotes, meters or anything that won't typically run dry in a days shooting, they are great.
In the last year, I've picked up some new Energizers. They don't actually say ULD on the package, so I wasn't sure what I was getting. But I've found that they hold a charge much better/longer than the old ones.
The recharge rate with all the NiMH batteries I've tried, has been very good. The big benefit is that they maintain a pretty consistent recharge, until they are down to 10-20% (almost dead)....then they slow down, so I know to change them right away. With Alkaline, the recharge rate slows down gradually, which is a PITA. Back when I used them, I would use them in a flash until I noticed the slow down, then I'd put them in remote controls or kids toys and they would last another year. Plus, they usually end up in a landfill, which doesn't sit well with me.
The one thing about lithium, is that they are light. In the odd case that I had to measure every ounce I carried, lithium might be an option...but again, not rechargeable.
Too bad they can't make lithium
Ion batteries in a AA format.