A simple, classic, clean and sharp look!
This one's a MUST HAVE in your collection, I use it often along with a select few other ones that I like, I try not to keep too many themes or addons in my list so not to clog things up in the browser, but having a few themes you like won't hurt, afterall, they're not active or slowing down the browser in any way if they're just sitting there in disabled mode.
Add this one to your collection of most used addons, you won't regret it!