Personally I fly Sanyo Eneloop NMHI batteries in my smaller planes ( 60 to 125) size Nitro and some Electrics with out BEC's  Great Battery 2000 MAH and holds a charge for ever.  But for my big Gassers I've gone to 2500 Mah LIFE 2 cell packs from Hobby King. About $9 shipped. I use two in each plane with 2 heavy duty switches, some through a Batt Share some plugged directly into my Aurora 9 rx's. the reason is that the Sanyo Eneloop's don't have the out put for the larger loads of the Bigger servos. Just my 2 cents worth. I also have the luxury of being able to remove and reinstall  the LIFE batteries in my big planes quickly.