Last night I rounded up my collection of detectors (including a brand-new RX65) and guns and made a video which I posted in the Videos area. Here's a link to the video for those who don't feel like hunting for my other thread:
Toward the end of the video, I ran all 3 RDs together. At the end, when I was shooting my Pro Laser II with all 3 RDs on, I pointed the gun in different directions, at walls in the room, so the detectors only saw reflections. The V1 and RX65 alerted every time, but when I pointed the gun at the side wall, the X50 didn't alert. I was able to repeat this multiple times. I even swapped the positions of the RX65 and X50 in case one had a "positional advantage" over the other, and I got the same result.
I was surprised by this, since GOL and other reports have shown the RX65 as being the weakest in the top 3 for laser performance. Maybe they improved it in the M4 version? I wonder how it would compare with an M4 X50.