Hey There, I just replaced my battery from a website called macbookbatteries.com, used the iFixit guide, and it works, but the battery dies at 30% every time, which is exactly what it did with the original battery. I took it into the GB and the new battery failed, I am guessing because its just third party, but power supply passed. My question is, does anyone recommend a good battery that doesn't die so prematurely? This one has a 1 year money back guarantee, it's why I bought it! But I am just not satisfied and really want to keep my laptop running great. Oh, it's an early 17" Unibody. Any help would be greatly appreciated!