Usually only the brand batteries are good. If you buy a cheap batteries @2200mAh, they are most likely 500mAh or so. So basically they just lie on their ads.
just from my personal experience. I had an older point and shoot Sony Digital camera which accepted both AA batteries and Sony's battery packs. I bought an off-brand battery pack because AA's were dying faster than I can turn on the camera! Anyhow, the off-brand died and didn't last mcuh longer than AA's! I was baffled!??! Never again will I buy off-brand... at least not for Sony products.
The best thing to do really with a digital camera is to invest in rechargeable batteries. These last extremely long for me and are great. You should be able to pick it up for around 20 with 4 rechargeable batteries. It has really helped me so much.
Recharchables still do not last as long. Cameras wi th their own special battery packs last the longest. It's usually worth the price tag. As for me, I just picked up a Canon 20D! Excellent camera.
