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I use Rayovac AA batteries, but they are generally pieces of crap. I wouldn't trust them.

For laptop batteries I would always go with genuine ones, I've had some bad experiences (though not with MBPs it must be said) with third-party laptop batteries, they're a false economy.

BTW if you go to an Apple Store and exchange your old battery or a new one, they will sell the new one to you at a discount.
 
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