You will now start a long procession of dos and donts that will never give you a full and decisive answer - because its full of myths, heard it from a friend, of a friend, its reported so often that it has to be fact ...
Thousands of people around the world use non original batterys. Most are not posting as I believe most are not on forums and TBH - why should they ?
All I will say is that of all the Phantom flyers in our Club ... 10. Each has average 3 batterys. Only 1 battery for each person is original as that was supplied with the Phantom. Rest are 3rd party. We have had only one battery failure and that was an original battery. That is fact and not hearsay or secondhand / thirdhand story.
You will hear about Warranty Refusal is your Drone fails when using one ... that's BS .. and I know that for a fact as I have had my P3P repaired under warranty even though they knew I used a Kiendle 3rd Party battery. They stated that they would only refuse warranty if the battery itself caused the failure.
I am sure now that someone will now post contrary information.
I have several genuine batteries and two newish after market batteries and so far no problems any, the switch of one of the after market batteries can be a bit tricky but that is just a slight inconvenience
All boils down to what you are willing to risk and of course opinions.
I’m one of those that only use original batteries and there are two reasons.
Number one is the cost part isn’t an issue for me and number two is I’m not willing to risk a one thousand dollar ac over trying to find a cheaper battery and have a problem because I didn’t find the right one. I have no doubt that there are those out there that use the non DJI products all the time and not have an issue. I’m just not in that crowd.
I have a total of 5 batteries. 3 are OEM, 2 are aftermarket. I've not had a single problem with the aftermarket yet, but they're relatively new. The OEMs are getting older with lots of cycles. I have no reservations using either. As Starz said, it's what you're willing to risk. OEM batteries fail too. That's a risk you take every time you fly.
The only drone that never crashed is the one what never took off...