FWIW, my experience many years back was that NiCD batteries were pretty useless. NiMH batteries are much better, and to me, the latest "pre-charged" NiMH batteries (aka, low self discharge NiMH, hybrid NiMH, ready-to-use NiMH -- which started with the Sanyo Eneloops) are great.
About 10-12 years ago, I picked up some NiMH AA's and a battery charger from Radio Shack. Lasted about two charges, maybe a bit more. The problem isn't/wasn't with the batteries but instead with crap chargers.
Right after that, I picked up a high quality charger from thomasdistributing.com. Since then, for the past 10 years, my experience has been great. I don't know whether the Duracell and Energizer chargers are crap too. Probably that is their new business model -- get people to try rechargeable AA's with their crap charger, the batteries won't last at all, and then people will say rechargeable batteries are crap, I'm sticking with my disposable alkaline AAs.
As much as I said that Duracell and Energizer battery/charger combos were widely available (to make life easy), I really personally would recommend getting something like a MAHA smart charger from thomasdistributing (which are only $15 or so) and a set of 4 NiMH AAs for another $10. It would be $25 well spent, and probably much better than the Energizer brand.
Also, fwiw and ymmv, but I think NiMH is a much more reliable, robust, and durable rechargeable battery technology compared to the Li-ion or Li-poly rechargeables that are used in the DR100 mkII. Li-ion and esp Li-poly are much more prone to failure. Though again, a good charging circuit probably helps loads, and the DR100 may have that.