If the capacity is spelled 2500ma, 2500mah, or 2.500 amps (unlikely listed that way), it all equals the same thing. The higher the capacity the longer the run time. In modern AA nimhs I'd never buy any lower than 2500ma, and in fact would shoot for the highest capacity I could find at a reasonable price.
I've never really read up on the eneloops but I think they are just typical nimhs but claim low self-discharge on the shelf if I remember right.
Part of the reason why many claim they get low run times from nimhs or nicads is because they charge them and then let them sit on the shelf for weeks, which in turn causes them to self drain. There are various nimhs now with low self-discharge so they are still near full charge even months after charging.
You need to read up on those though because some low self-discharge nimhs don't hold up to their claims. I wouldn't mess with anything but low self-discharge nimhs these days in a detector unless you don't mind topping off a pack say every week or so between hunts to keep it ready to go. Some nimhs are worse than others at keeping their charge on the shelf, but the low self discharge ones (some of them anyway) are much better at holding the charge in storage.
I find 2500ma or higher AA nimhs give me longer run times than non-rechargeable AAs. Also, while a nimh may start out with a lower voltage than a non-rechargeable it will hold it's voltage higher longer, so sooner or later the non-rechargeable will be running at a lower voltage than the nimhs. Nimhs/nicads tend to flat line their voltage and hover near 1.2V for most of the discharge, where non-rechargeables will tend to drop their voltage more steadily as they drain.
I think those Enelopes are kind of pricey ain't they? If their main claim to fame is low self-discharge I'd check into the numerous other low-self discharge nimhs out these days. I think the enelopes were the first to make those claims, so I bet there are much cheaper options now a few years later. Just do your research and find out who's claims actually are true. Many independent guys who test batteries for fun in their free time who have some excellent research data on this stuff if you look around on the net.
Think I'm finally home after a lot of years searching for my particular needs. Custom 1.5 lb lighter 
Sovereign GT (easy to do by just "building" lighter shaft) & SEF 12x10 as everyday coil. 8" Tornado (actually 7.25") as super heavy trash coil (Very deep & separates better than typical 8/9" true size coils). 13" Ultimate for large fields/beaches on certain days I want to grid faster than even the 12x10's nice improvement over stock for that. Stock 10" Tornado stays on water rig (stock shaft). 
ProPointer. Owned 15x12 & SunRay S-5 (5.5") at one time. Loaned a prior 13" Ultimate & SunRay S-12 (12.5").
Some Oldest Silver- 1835 Bust Dime, 1842 "O" Seated Dime, 1855 Seated Quarter, 1858 3 Cent Piece, 1891 Seated Dime, & another Seated Quarter too damaged to read date. Highest Value- 3 Cent Piece, Seated Quarter, & now 1921 F-12 Standing Liberty. Oldest Coin? Got to give large cents a good look & see. 2013 so far- 1 Seated Quarter, 1 Barber Quarter, 1 Standing Liberty, 2 Washingtons, 1 Barber Dime, 9 Mercs, 3 Rosies. 1 War Nickel. 19 silvers in total, & 1 1872 key date Indian, 2 Bufallos, 1 man's 14K gold medium sized ring & 1 gold chain, with possibility of few 8"+ deep mystery coins being Indians after cleaning.
What matters in life is the journey and not the desitination. How you handle that journey determines if you were a success, not so much what you achieved if and when you finally get there, especially if you made it by stepping on people along the way...
In loving memory of my long haired (wooly) husky Sky. She taught me just how beautiful and pure a soul can be, human or not...
