I bought it. Yeah its expensive as heck for a rear light. I find that with bike gear, I can do a cost/benefit analysis and avoid the stuff I think is crazy expensive. The benefit is astronomical when it comes to being seen so I have no compunctions about buying an expensive light if I think it does the job well. This light does.

It has a low light indicator which is very useful.

The seatpost attachment is quite good and easy to use.

Most importantly, it is a bright rear light and it is not directional (like most of the bright rear lights I am familiar with).

Light and motion makes a quality product.