I have the Otterbox Defender and have not had issues with the nfc phone to phone transfer. However, I found a pop machine that actually accepted isis payment with the nfc but I think the case is too much as it would not find it. I didn't feel like taking my case off to test the theory.
Well don't take this as 100% confirmation, but at least between two galaxy s3's with urban armor gear on bought nfc worked fine.
I'm not yet got urban armour gear to my s5 that's why I had only tried nfc with that case on my old s3.
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