Well I guess Skyhooking is good in cities; I take a lot of photographs in remote rural areas. But even some location data is better than none. Still, that would be one point for the iPhone solution. Another is that it’s likely to be cheaper (factor in also that eye-fi expect you to pay the additional Skyhook fees after the first year).
I imagine there’s battery drain on your camera from the wi-fi so we’ll call that a draw. Especially as I’d be willing to switch the iPhone background log on or off in settings depending on whether I’d be taking photos (I do something like this with 3G when I’m going to be a long way from juice and my need for fast broadband is second to my need to keep the phone running).
A point for the eye-fi is that it also gives you the cool (if non-essential) wireless upload of pics.
Points against the iPhone solution: it’s just a rumour…