Elmer, RainX has cost some reflection, but compare to the semi reflective lens of the Reflex or the Aimpoint, the reflection rate is still much lower.
Peopel have complain about the sight can gather snow or mud, but as long as there is a partial opening on the wiondow, you can still acquire target. even if your lens is completely cover with junk, you can always use your EOTech as a OEG styel sight. Rain droplets has not been a problem for me, then again I live in Kalifornia, what would I know about rain?? [;)]