As you noted, there is a difference in magnification ranges.
Another difference is the adjustment values - for the XP50, one click is equal to 34mm at 100 meters, while the XQ50 has click values of 20mm at 100 meters.
Weights are slightly different with 1.36 pounds for the XP50, and 1.23 pounds for the XQ50.
The microbolometer on the XP50 is 640x480, while on the XQ50 it is 384x288. The detection range is the same for both - 1800 yards.
Mark H.