Looking over this item on a supplier's site (who shall remain nameless

.
It provides all kinds of info (G-force, acceleration, distance, horsepower, etc.). A lot of the data it provides can be documented in other ways, but if it really does it's job, or even most of it's job, it could be useful. I'm considering sharing the cost of one with a friend.
Anyone own one of these?
Are these just a piece of crap? Or a useful gizmo?
What's the skinny?
Ignor image below - just a test.