I got it and it works good, it makes the club feel different when you swing it cause it adds a little weight to the shaft, and it is real close on the actual speed. You can set it up to your height and change the lenght of clubs to adjust for different clubs you use to check the swing speed for all the clubs in your bag, batteries dont last very long, i have used it about 5 times at the range and already need new ones.
Here is another alternative that I use. Swing Speed Radar with Tempo Timer for Golf
you don't have to switch it around on different clubs and it wont effect how your club feels. Works great for speed and tempo, although they have a cheaper one that just does speed.