I'm sure the effectiveness will be dependent on a number of parameters like the height of your windscreen, your height, your distance from the screen, etc. Also, if you have a tall screen, are you already looking through the screen, or do you look over it? If you're looking through it already the Laminar Lip will be directly in your line of sight, not a good thing.
As to looks, well, its a big hunk of plastic stuck to the top of your windscreen with four black velcro dots. The upside is, the Rocket isn't really a beauty to start with. I wouldn't put one of those things on a Ducati, but a BMW GS or a Rocket, sure.