OMG! AERO HAX!!!
Serously, though, it's probably of minimum benefit for most of the conditions most of us ride under. Probably shows some improvement on the Velodrome, or sustained high speeds coming down a CA mountain pass.
More noticeable benefit to be gained under '99%' conditions by a low-spoke-count 'semi-aero' wheel with bladed spokes and good hubs. Heck, probably more benefit in fitting quality high-end tires.