Here is a link to a very extensive test of various rechargeable AAs. It includes a side-by-side table that is very useful:
http://www.imaging-resource.com/ACCS/BATTS/BATTS.HTM
This tester used the batteries in digital photography which no doubt beats up the batteries more significantly than the JBL, but one would think that his results are still credible and indicative of battery performance in general.
Interestingly he has one Energizer in the #1 position (2300) and another way down on the list (1700). I guess it does matter to pick the right Energizer if that is what you are going to purchase.
This is a great thread which will go a long way in helping me choose my rechargeables. Thanks to all involved!