I am skeptical about this. $188 is a h311 of a lot of money for something a long enough straight-edge will do (and not need batteries for.)
And this line on thier site bothers me too: "If your bike seems to “prefer” one type of turn over another, it can be a sign that your wheel alignment is not properly set."
All humans tend to favor one side or another, and as a result, right handed riders will tend to feel more comfortable taking left hand turns, because their sword hand will feel less threatened. By attributing this human tendency to some fault in a machine's alignment...it's just not 100% honest.
And if you really want to use a lazer to align your rear wheel, every hardware store has lazer-levelers for hanging picture frames straight in your home for a lot less than $188. Lots less.
Good luck either way.
-CCinC