I love the design of the Lexar Firefly drive! The cap fits snugly, and has a hole in the cap that provides an attachment point for key rings, lanyards, etc. The Firefly drive detaches from the cap so that it can be used solo in a computer's USB port, but the cap is reversible so that it can be fitted on the body of the Firefly with the USB plug exposed. It's a very good and flexible design. The body of the Firefly is only about an inch long exclusive of the USB plug and has just enough thickness so that it feels solid and well built. A blue LED illuminates the entire end of the Firefly so it's easy to see when the drive is being accessed.
Recommend this product?
The speed of the Firefly is reasonable, but it won't win any prizes. Writing twenty-five 3 MB files to the Firefly took twenty-three seconds, and writing one 100 MB file to the Firefly took twenty-five seconds for write speeds of between 3 and 4 MB per second. That's fast enough that unless you are writing a large number of files, you'll be reasonably happy with the performance. Read speeds are much faster. I read 350 MB of data from the Firefly to my hard drive in just under thirty seconds. That's better than 10 MB per second, acceptable for most purposes.
I think the good design of the Lexar Firefly trumps the mediocre write speeds.