The problem with most rechargeable batteries is that they don't hold their charge well. That is why I now use Sanyo Eneloop. While its AA sized battery is rated at only 2000 mAH, its true capacity is actually very close to 2000 mAH as stated by Sanyo. As for the Powerex, it may be rated at 2700 mAH but its true capacity is considerably less. This was the result of a study on batteries that I stumbled across in the internet.
Besides holding its charge better, the Eneloop also last longer because you don't have to charge it until the charge is depleted and the lesser the number of times you charge, the longer it last. Furthermore, as it is only charged when the charge is depleted, it also suffers less from memory effect.
Would I go back to 2700 mAH batteries again? Perhaps yes if I am an extremely heavy user. I still use the Powerex 2700 batteries I have but any new batteries that I will buy will be Eneloop or equivalent for sure.