Pros: Easy set up, accurate identification, and downright neat!
Cons: I think of none. Just use your head. The light doesn't bother me at all!

My son bought me one for my birthday because I didn't want to part with the $40 to buy one myself. Now that I've got one, I'm getting one for myself at work, one for my wife, my Dad, and probably a couple as gifts. Aside from being terribly cool, it really cuts down on the time you spend entering passwords when you hop from secure site to secure site. It even worked really well with ESPN's Insider - which is a pain in the posterior to log into on a GOOD day!