I had two Rev.5 X50s, one of which I just got rid of. I kep the one I felt was the better detector. It always alerted a little earlier and stringer on falses, noticeably, despite it being a few years old.
The wife and I decided to travel to the West coast of FL yesterday, from Palm Beach, and the road is 1 lane, both ways through just about nothing but a couple of small towns. I know it's a haven for speed traps though.
X50 rev5 mounted center windshield (leveled) gave me 5.1 miles from the first Ka alert to the LEO. It gave me about 3.2 miles from the first alert that continued to the LEO. The 5.1 mile warning was a single alert, followed by two more before the continuous alerts started.
Granted we were on as flat, as straight, and isolated a road as one could find, this performance is still fantastic.