I'm using the Eye-Fi Pro X2 8GB with my 5D3 and also Olympus XZ-1. Had some trouble setting up initially but finally managed to solve it and now it's working perfectly. Very very convenient

But it's advisable to transfer only Small JPGs since it takes quite a while to transfer. Tested the wireless transfer rate and it's about 1MB/s. So if you're JPG is 5MB it'll take 5 seconds before it appears on your iPhone/iPad/laptop etc.