Found a review that stated, "Taking the average size of a 10MP image from a Nikon D80 set to JPEG normal, which is about 2MB, and dividing that by the ~15 seconds it takes to transfer each image I can calculate that the approximate transfer rate is 135KB/s"
And on http://www.maximumpc.com …eyefi_wireless_flash_card
"So what’s wrong with it? Speed. It took roughly 6 minutes to transfer a 5MB image over our corporate LAN, which has 14Mb uploads and 30Mb downloads. Bang out 35 photos, and you’ll have to leave the camera on for the evening to upload your pics. Fortunately, the images are also stored on the card, so if you shut down, you can resume your upload later. What is wacky is that images are sent from the card to Eye-Fi’s server, which then disperses them to your website or PC. The impact on battery life is difficult to gauge but is certainly a drag. The card also can’t upload video or RAW files and doesn’t work with access points without security or in peer-to-peer mode."
My son in-law has one.