Had one, now got photon xtreme. Easy to setup if you use adjustable mounts (like atp66), otherwise crosshairs are nin central in screen. Add a decent ir and bunny bashing at 120-140 yards is ****ible but i never went beyond c100 yards on hmr.
Just moved mine to my 243. Always had it in QR mounts and never had a problem getting it zeroed and the cross hair has always been central. I have heard lots of people have issues getting it zeroed though.