Mine arrived today. Here is my verdict. I'll reprint my email to APEX verbatum.
"Please generate a return number and a shipping label for the carrier of your choice.
To put it bluntly, this thing is a POS. That the housing is plastic is not necessarily the problem, the fact that the rail interface portion of the housing is, is. And a crappy design on top of it, it's one molded piece with no way to open up the mounting dovetail section to mount the unit directly down on top of the rail, then tighten it up. Even trying to slide it on from one end is problematic, there is an "interference fit" such that there is more plastic for the male projection than the female slot on the rail allows. This is the case with two different weapons. I'm not going to trim it down so it fits. It should fit already.
Disappointed. You guys used to be better than this.....''
Bottom line, if you need inexpensive, try Vortex. Otherwise, buy the good stuff. Aimpoint, Trijicon. For a little bit more.....