You can see the discharge curves of the different batteries at candlepowerforums. There is no significant difference between major brands, including rayovac and the better store brands. The main difference is price, shelf life, and tendency to leak. Like others, I have had a lot of alkaline batteries leaking on me, even found in-date brand name batteries leaking in the package. It's to the point I won't put alkaline batteries into something I like, not even remotes for my stereo equipment which could be hard to replace. I either use Eneloop or Energizer lithium AA which, as far as I know, can't leak like alkalines. The lithium AA are twice as expensive but last at least twice as long so it's worth it to not worry about ruining a device. By the way WHEN alkaline batteries leak it's potassium hydroxide mostly and straight vinegar cleans the mess up pretty well.
