If you go with eye-fi, I highly recommend using the Shuttersnitch app rather than the stock Eyefi one. It will do some nice stuff, like warn you of exposure issues or slow shutter speeds on long lenses (etc, etc, etc -- you can select different conditions to produce warnings)
ShutterSnitch
Personally, I had so many issues with the eyefi connection (that was when I was still on Nikon) that I ended up returning the iPad I'd purchased primarily to use for this purpose. I haven't actually tried it on my K5, though, and my phone connection is much faster now, so maybe I should dig it out and try again.
Definitely shoot in raw+jpg with the JPG set to the smallest size and lowest quality, if you plan to use it just to review your photos on a bigger screen. They can handle RAW, but the files are so large it's not really usable. (but if you're using it to immediately upload photos for your protection in case your camera gets confiscated at a protest or something, do whatever size you need).