I present to you, the world's ugliest case.. Hahaha, this case is not for esthetics not does it provide much protection for the phone but it does pack a 10,000ma battery. Does it add weight? Does it add bulk? Is water wet? Hell yes! But surprisingly enough, it's comfortable in the hand.
Supports data sync as well, BUT not Gen 2, 3.1 cables.. You know, the ones that support 10Gbps data and high speed file transfers. At least, that is what I've experienced.
The case will charge your phone at standard charging speeds (in other words, not fast). If you plug a charging cable, it will charge your phone and the case, but your phone will still charge at standard speeds regardless of your adapter. Bummer. You can also charge the case wirelessly... but also at regular speed and not fast. So ya get it? Nothing is fast.
But I got it mainly for the few times I need constant juice if I'm recording a lot of video and having a battery pack and cable would hinder my recording. Otherwise no way is this my go to case..unless I need a work-out.
It's good if you don't want to carry something separate and don't mind the weight. But if you can deal with a battery pack and cable, then I'd stick with that route. I have a 10k ma pack that supports superfast charging that will do the job quickly. I'd sort of really think of situations where having it plugged in is going to be a hinderance and you don't have an hour or so to let your phone charge.
BTW, Samsung Pay and NFC works!