“All journeys have secret destinations of which the traveler is unaware.” – Martin Buber
jtan163: Seems to me the EyeFi is designed for pros on formal shoots, perhaps with a digital tech and to replace wired tethering.
The transcend seems more for the hipster dufii snapping selfies and what they had for lunch on intsagram and FB.
Actually, the opposite is true in my experience.
I have both of these WiFI cards and have used them in various cameras but mostly in my Olympus OMD E-M5 and my Canon 7D (with CF adapter). I also use the ShutterSnitch app. I only use the native apps if I absolutely have to. Both of them are terrible.
After months of use, I find, for my needs, the Transcend works much better. It takes a little more time to set up and the firmware upgrade has made it much more stable but it transfers faster and works better with ShutterSnitch on my iPhone & iPad. The Transcend is also double the memory capacity so hooray!
Don't get me wrong, the EyeFi card works well and is very nice. It's very plug & play if you don't want to spend time in settings. Their app is also easy to use, better than the Transcend app, no where near as good as ShutterSnitch.
It really depends on your needs. I think more serious photographers should look towards the Transcend card.