I would say oem.. But I did get an aftermarket battery from my mom for Xmas ( she didn't realize there was fakes out there) so far I have used it with zero issues.. It lasts just as long as my original p3 battery's, looks slightly different and says "compatible with phantom 3" Instead of "phantom 3 Intelligent flight battery" like the real ones do..
As I said it works just fine, I have heard of ppl saying that the dji go app will know it's not an original battery and will shut the props down during takeoff but mine is working just fine, but it is another reason why I won't update.. Cuz if I did I'm sure it would stop working.
That being said I still for some reason don't feel at ease with it.. Even tho it performs nearly identical, maybe it's just in my head but I don't feel super safe with it, but I couldn't return it as it was a gift.. So I use it, but when I do use it I stay close with it incase something funny starts to happen.. Imo go with an oem battery and save yourself the worries if nothing else..
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