Right now.... There is some degree of validity with regards to a lot of comments posted here.
The SwingBytes device is a bit annoying as it has a hard time remaining both synced up and properly aligned on the club.
It is good for having a rough analysis of your swing plane and speed. I actually slowed down to see if it would follow my every move (it did). It does have a hard time maintaining sync via bluetooth.
I got it for 101 bucks off eBay. You get what you paid for methinks.