Personally, I have been most impressed by the Boomslang's mouse wheel. I think it's the best in the business. Also, they're obviously using very high grade plastics for the thing. It just feels "right." Too bad the mouse is a little big and a little too sensitive on some of the buttons; otherwise, it would be the undisputed champion of precision mice. Nevertheless, it's still got more precision than anything else out there (by a mile), and it's the coolest looking gadget I've seen in a while. Read Andy's review for the whole scoop.