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.
My tech21 Impact Mesh case fits over the official wireless charging back and doesn't seem to interfere at all with NFC or wireless charging. I'm loving this case.
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.