On the face of it, this is an excellent concept; a USB key without any of the bulk, making it a very appealing proposition for those of us who want as little bulk as possible in our pockets.
The Iamakey worked great for me... for about 3 days. Then the following day I arrived in work to find that the key simply wouldn't work. My PC would recognise a removable drive, but it couldn't read from it, write to it, or even format it. It was as if the disk controller within the device had failed. Even worse, I'd lost a key presentation I was working on that I was due to present that day.
Even now I am not sure what caused the key to fail. However on testing it further, it became clear that the contact between the key and any USB socket (and believe me I tried a few) was very easy to break. This "open top" design is all well and good for cutting down on size, but in my experience the reality is that it means the device doesn't get a good, solid connection to the USB socket.
Any which way, the Cruzer 4Gb key I was using for some 2 years before (with no faults - ever!) is now back on my keychain, and I think I will steer well clear of these open-styled USB keys. After all, if you do not have complete faith in a device operating 100% of the time, you simply aren't going to trust it or make any use of it. A shame, as this could have been a really amazing bit of kit...