I would like some advice regarding the use of non-Olympus branded batteries. Generally I don't need a spare battery, but we're planning a vacation and I feel having a extra handy would be a good idea. I've checked out Amazon. and they have at least 3 brands, some that charge with the Olympus charger, and others that come with a charger. All are substantially cheaper then Olympus, and would be hard to pass up. Anyone out there with experience using off-brand batteries, I would like to know what you think. Thanks for your help.