I'm using WIFI card .. been using it since last year after I gotten my OMD ..
I have the 8gb x2 pro and following is what I find about the card
The card is very easy to setup .. I experienced non of the problems that most people complained about ..
either I'm lucky .. or I don't use Apple products since most complaints are with Ipads and Iphones (even though it is rated for use with apple)
My card is set up to route pictures 3 ways and depending on your preference .. however you like to set it up
Camera -> Phone
Phone -> internet
internet -> desktop
I did it this way because I always carry my phone .. the tab and pad are not my normal carry items ..
I set WiFi only so the photos only transfers to internet whenever I have a WiFi connection ..
Once its uploaded to Internet .. it is automatically downloaded by my desktop ..
For me .. I don't have to manually connect to my desktop to upload the pictures .. or transfer images myself
Its basically a lazy mode for me
On occasions I get issues uploading pictures to the web .. and it takes a few tries before they are uploaded ..
The card is set to 80% .. so whenever it reaches that capacity .. it will start deleting files that have been transferred ..
so I actually have a virtual unlimited sdcard ..
couple of things I find not to my liking
I can't directly upload from my phone to my desktop (it has to go to internet for some weird reasons)
you have free Eye-Fi account that stores your images for 7 days online .. unless you pay something like 24usd per year ..
the card has to plugged to a desktop to change the configuration .. even though the configuration is painless .. I'm just lazy
You can only upload the files to one location at any time .. ie if I change phones .. I have to plug in the card to the desktop to change the location to my new phone
As for the question about it being a class 6 card .. I don't know how that works .. as in where you see the benefits of using a class 10 over class 6..
the only way I see is when you're taking high framerate shots .. but I tested it on my camera and there was no difference .. 15fps before it slows down dramatically (using EyeFi and Transcend 16gb Class10)
any other questions regarding the card do let me know
Richard