Hardware
There's never much to say about the outside of a USB thumbdrive, but the IUM could certainly be a conversation piece for some, given the way it sticks out of anything you insert it in like a... well, like a big sore thumb. The dongle is red and proud of it, with curves and vents no doubt designed to evoke a flashy Ferrari, but held back by the quality of its construction -- the USB board floats (and rattles slightly) in a hollow plastic shell that gives slightly when squeezed, albeit covered with a soft-touch rubber coating that makes it comfortable to hold. There's a three-color LED on top for reporting connection status, a lanyard (and cap storage) slot sticking out of the back, and a flimsy switch on the right side for swapping the IUM in-between "infinite" and pairing modes -- more on that in a sec.
Setup

First, you place the drive in pair mode, and connect it to your Windows PC, at which point it gives you access to the install files on the internal flash. After installing the software, you still need to actually pair the device with your PC, so you have to assign it an SSID, password, choose your WiFi encryption settings and pick an "upload" folder for any items you might have copy onto the drive. After syncing that information with the IUM, it's ready to be unplugged, but you can't use it quite yet, because you also have to choose how large the drive should appear to be to devices that you plug it into -- and the larger you choose, the longer the drive will take to connect. Once that's complete, you then have to click on a different tab, manually pick files and folders on your drive to share and process them for a little bit, because you have to create a virtual filesystem that you can beam over to the drive -- and we couldn't just say "process the entire hard drive" and be done with it, because the software choked on that request. Got your files lined up? Then you're ready to switch the IUM into infinite mode, plug it into your device of choice and wait a tedious couple of minutes for it to automatically connect... assuming that both you and the installer software did everything correctly.
The installer is supposed to do a pair of fairly important things in the background without even letting you know -- create a pair of firewall exceptions for the IUM, and install Adobe AIR. Of course, if either of these things fail for any reason -- it did repeatedly with us -- you're going to have to do some troubleshooting yourself, and not the easy stuff. On all three of the host computers we tested the IUM with, it failed to play nice with our standard Windows Firewall (two out of three didn't work with AIR) and we ended up having to manually open ports on one machine and manually connect our WiFi to the IUM to get things paired. The third computer, inexplicably, wouldn't work with the IUM at all -- it kept complaining about firewall issues even with the firewall completely turned off.
Performance

As we alluded to above, the connection also wasn't completely reliable even up close, and displayed erratic behavior of various kinds -- sometimes it would drop speed suddenly to a few hundred kilobytes per second, only to shoot up to several megabytes per second and then back down again when transferring large files. It also occasionally disconnected completely in the middle of transfers or when browsing files, and when that happened there was no waiting it out -- the only solutions were to manually stop the IUM service, or unplug the drive. Last but not least, it's important to note that the IUM uses up your host computer's WiFi connection, so you're not getting any internet access from that computer while you're sharing files, and though there's a theoretically impressive "dual-WiFi" workaround for this particular issue which uses the IUM itself as a wireless bridge, it's subject to the same range problems as the IUM itself, and couldn't even see, let alone connect to an access point located only a couple of rooms away.
Wrap-up

