I bought a battery from Amazon last spring for my early 2011 15" MBP that was a pile of, well, you know what. In the fall I finally decided to replace it with a refurb 2017 15" MBP and am for the most part very happy with it. Using my old MBP a few days ago did make me realize two things about it though. The newer ones are so much lighter (over 2lbs ~1kg!) lighter and man the keyboard on it sucks compared to the old one. It's also my first retina laptop which is so much nicer than the old displays.