I've got a Rev B 12" PowerBook, with the original battery. The battery's has a really low capacity for a while, but has just failed entirely, so it's time for a new one. Now, I could get the official Apple one for £89, or an imitation one from eBay for around £43. Given the price difference, and the fact that the Apple ones seem to go bad pretty quickly (check out the reviews on the store for the 12" battery!), I'm currently liking the cheap option. Does anyone out there have any experience of the imitation batteries?