The fractured foot probably slowed him down this season, because he looks quicker in some highlights than others. Regardless, he definitely seems fast-enough and quick-enough to be an effective NFL receiver.
It's difficult to judge college WRs, because there is so little press-coverage in college and lower-tier CBs are nothing more than traffic cones to the top-tier WRs. But Crabtree's speed and quickness look better than expected (his receiving instincts have never been questioned).
For what it's worth, back when JJ Stokes was selected, I never bought into the hype. I remember watching his highlights and immediately being skeptical of his speed and quickness; he was tall, lanky and just appeared slow as molasses. Forget about the cost of trading up to #10, I just wasn't happy with JJ as an NFL prospect. With Crabtree, I don't get that impression at all. I think he's got enough pure physical tools to be very good in the NFL.
Now Glen Coffee is another matter...the more I watch him, the less impressed I am. =(