The Apple iPhone 6s might be the one that is being called out for having a faulty battery but it is the Apple iPhone 6 that is the unluckiest on of the lot.
Although the Apple iPhone 6s is the one that is being mentioned right now, the nice part is that Apple has actually agreed to make it up to their users for free. The Apple iPhone 6, on the other hand, is still being ignored despite various reports claiming that the users are also having the same battery issue.
It does not seem like Apple is planning to offer any sort of fix for their iPhone 6 users which mean they will either have to bear with it or get an updated model. They might also want to consider getting the Apple iPhone SE model.
Even though the device was fitted with the same iPhone 6s hardware, there has not been any reports of the device having the same battery issue. The iPhone SE was fitted with the same A9 chipset, 2GB RAM, and 12MP camera.