As chronicled in this blog post, our main purpose for attaching a USB drive to a keychain is to have handy access to files. Testing several new laptops every week, key drives are useful for storing and transferring all the install files for software apps that should be on a new laptop, but aren't (such as Firefox, AVG Free, and Open Office).
LaCie claims the drive offers transfer speeds of up to 30 MBps in read mode and up to 10MBps in write mode. Our tests, using 6.68GB files, found this to be close to real-world performance. Writing the file took 12 minutes and 32 seconds, for a transfer rate of 9.3MBps; and reading the same file took 4 minutes and 29 seconds, for a transfer rate of 26.1MBps. That's typical for USB flash drives, although some models can offer nearly twice the write speed.
Thinner than plastic USB keys, the IamaKey is 2.2 inches long by 0.94 inch wide by just 0.12 inch thick--about the same dimensions as a typical house key. Both 4GB ($26) and 8GB ($36) versions are identical, and the actual USB connection on the end is gold-plated, which LaCie claims makes the drive both water- and scratch-resistant. That's a good thing, as the tiny translucent plastic cap that covers the end seems like it could fall off and vanish at any time.