As an OSU alum, I've followed Ginn closely. This doesn't surprise me at all. I've said that the thing that's special about Ginn, the thing that he has that I've in very few players before him, isn't super human speed, it's super human acceleration. Case-in-point, the Fiesta Bowl against Notre Dame. One minute the DB is running step for step with Ginn, the next he hit's the afterburner and has a cushion of 5+ yards. He plucks the pass out of the air for the easy score.
That being said, I wouldn't touch Ginn with a 10-foot pole. It's not a lack of speed that scares me. It's the fact that Ginn is a much better athlete than he is a wide receiver. He has two qualities that absolutely terrify me: He is a very sloppy route-runner and is often prone to longs stretches of drops. Watch the OSU-Michigan game? Ginn dropped not one, not two, but three passes that hit him square in the hands.
I understand the philsopohy that you can teach a guy with world class speed/acceleartion to run better routes and catch, and you can't teach a guy that runs perfect routes and catches fantasically, but runs a 5.0 to be faster. The thing is, Ginn, IMO, is way too raw of a prospect to burn a top pick on.
He's a true boom-or-bust pick, but I'd elect to stay far away. (But not because "gulp", he might be slow".