Powerex low-self-discharge and Eneloop batteries seem pretty much equivalent based on my own use, and also from the research I've done each time I've replaced them (about 3 times in 10 years). So I'm still using the Powerex AAs, AAAs, and 9.6Vs with the Powerex chargers (the 9.6V charger is specific to that battery, the four-bay AA/AAA charger is their top multi-function model others here are using). I have Eneloops at work for our digital cameras.
Independent circuits for each battery, and "smart-charging" routine instead of a dumb timer-based routine are the most important features to have in a charger.
The more advanced features are nice for determining the actual battery capacity (useful for matching cells in pairs, and in determining end of life), "forming" new cells for maximum performance, and, "restoring" older cells for a second life in other non-critical applications.
I got the Powerex charger and it works great, once I figured out the programming sequence. The trouble with our hobby is that if you run one show the batteries are far from discharged so it is hard to get them fully charged again. The Powerex will discharge then recharge to capacity. It also analyzes to tell you your batteries are shot, which a lot of them were. I use the shot ones for remotes which don't need a lot of juice and not such a critical function. You can set the charge/discharge rate low or high, depending on how urgent your need is. If you have plenty of time, you can do a nice slow charge which for me is every time pretty much. I don't know how accurate it is, but it also estimates how many mAh each battery has when you are done charging. Definitely a huge improvement on the cheapo hardware store models which operate on a timer and wear out your batteries prematurely, overheating them. Worth the investment.
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Although this is/was important with old NiCad rechargeables, you don't really need to do this with NiMH batteries in a quality "smart" charger. NiMH + "smart charging" doesn't have "memory effect" in the same way when only partially drained and recharged. Using a "smart charger" you can safely fully recharge from an only somewhat discharged state without damage or ill effect. This is my standard procedure and I get full capacity from the NiMH batteries. Run the "re-fresh routine" on the Maha charger every 6-months to year or so which does a full automated charge-discharge-recharge cycle and reports true-remaining-capacity. That provides good lifetime monitoring and reassurance. The "initial forming routine" does the same but via multiple charge/discharge cycles. That can take a few days to complete depending on how you set it, and thus is best reserved for brand-new or revival and assessment of end-of life batteries for use in lesser roles.