i've got 'em. just put them on a few weeks ago. definitely an improvement
Have a similar pair from Wayne's World. As I recall, I thought they were an improvement when I mounted them. However, the number of variables associated with air management, especially the size and shape of the windshield (assuming it's mounted), make any comparisons from bike to bike and rider to rider something of a crapshoot.
Consider that what one rider considers to be a breeze another may consider to be a strong wind. I find that on the few occasions I've ridden without my calf-high boots, for example, there is a huge difference in the amount of air I notice on my legs. And when I switch between my summer and winter windshields, the entire configuration feels very different.
About the only product I've ever encountered that seems to earn almost universally similar comments (and praise) are Baker Air Wings. And as dorky as I think they look, I've recently purchased a pair.