I have a Stealth I390 and got six months life out of alkaline D size batteries. I have an Xtreme 5 that gets much better life with the rechargeable 12 volt battery.

This is why I've found that there is not one answer to this question. I've had cameras where the alkaline batteries gave longer battery life than rechargeable batteries and I have cameras where the rechargeable batteries gave longer life than the alkaline batteries.

So, I guess my answer is that it depends on the camera.