Make sure you buy the latest version from about 2010 onwards.
The early versions of Eneloops have had some bad press, but the latest versions outperform anything I've tried.
I'm an electronics engineer and very anal about batteries. I've tried and tested at least fifty different brands and capacities of NiMH in the last ten years. I've tried thousands of other types since my parents bought me my first science kit. I've even got a collection of ex-military NiCds from the eighties which still work fine.
You may think that your fancy brand name 2800 mAh AA NiMH are good, but some of the modern cameras will not give them the time of day. Although they may deliver 2.8 A for an hour, their terminal voltage drops quickly and they can have quite a high internal resistance. I've found that in some cases, the amount of starting current can be inversely proportional to overall capacity in these batteries. So, the 1000 mAh cells from the pound shop can often deliver more initial current than the 2800 mAh top brand cells. Some new cameras demand a high initial starting current that even branded batteries lose after only a couple of on/off cycles. Also, I'm always dissapointed that even good quality NiMH batteries can lose charge within a couple of weeks.
NiCd batteries, despite being very environmentally unfriendly, were always much better at keeping charge, terminal voltage and delivering a high current on demand. However, these new Eneloop batteries have at last turned the tide. They work straight from the pack, take months to discharge, keep their terminal voltage and despite lower capacity figures (2000 mAh), I reckon they easily outperform my 2850 mAh traditional branded NiMH cells.
You'll save money and the environment with these cells, as you'll recharge them less and they'll effectively last longer as a result.