He doesn't buy into the Check-Go, which is proven by science. But he'll hop right on board the Speed Stik Bandwagon, simply because Vijay is on board. Little did he know, he thought he signed on to endorse a deoderant, as the guy said "You stink, this will help" I'll tell ya....
Actually, I've never used one, but have heard mixed reviews mainly dealing with it's accuracy on speed. Just another option, that I have used and feel that you can get more out of it simply because you can use your own clubs and see the different results of different changes in your swing.
Just a little more than the Speed Stik.
http://www.swingmate.biz/
I have used this exact one, as it is what my old Pro and Clubmaker used for their testing. They can be found cheaper, but this one is probably the most common.