So, after a couple of weeks not using the Eye-Fi card, I decided to give it another try (mainly because Eye-Fi published the Direct-Mode and an update to the iPhone/iPad application). Now, while the card (or better the upload) is still quite slow, you can take a picture, wait a couple of seconds and see the photo full sized on the iPad. Quite nice, I have to admit. I guess I still wouldn't recommend buying an Eye-Fi card (unless they can be 'jailbreaked' somewhen...) but nevertheless, it's a nice thing to have.