I've got one installed on a HK USC, and I really like it. Mine's sighted in at 25 yards, but because it sits so high above the barrel the impact is lower as the target gets closer, but it is still close out to about 100 yds.
Mine is a slightly older model, so the buttons aren't as easy to use as the newer ones, but that is my only complaint.
One of the reasons I got it was that the reticule has no parallax error, but now I'm not so sure if that is a good thing on my particular application. I'm pretty sure that since it is a 2-dimensional reticule on a 3-dimensional hologram, that they manufacture it so that the reticule appears to be at some far-off distance, which is great if you plan to shoot at far off distances. I don't, as the USC is .45ACP. Apparently, you can contact the company and order a custom reticule, and I've been thinking about asking them about a 3-D reticule that has dots at several apparent distances, such as 25, 50, 75, 100yds, etc, so that I can get parallax to work for me. It may also help as a ranging tool, to use some constant MOA dot, like Shepard scopes do (unless they have a patent on that)
Sorry to get off the question a little, but the bottom line is that is is well constructed, works great, and a lot of thought and design have gone into it. Fast target acquisition, constant cheek weld not required. AA batteries have lasted me 2 years and counting, and don't cost as much as the camera batteries.
Hope this helps.