I bought a few. Only one was decent and still use it. For one of them I had, it never calibrated correctly and I think it was surging the motherboard (backlight on my screen just stopped working one day, but the computer just would keep turning off with it, leading to a lot of 'hold the power button down to clear the capacitors') ... the other one just doesn't charge past 65% anymore. Maybe that's a calibration issue; it sat awhile.

I am going to look at another vendor. Maybe GreenCell?