I just found this site. I am somewhat of a RD enthusiast. I have a Passport 9500i in my Z71 Silverado, a Bel Rx65 in my Duramax, A Whistler Pro 78 and a Whistler XTR-105 for spares. A vintage Whistler 1290 is in a drawer somewhere.
I have found the 9500i and the Rx65 to be outstanding RD's and I can't really tell much of a difference between the two as far as detection range of K and Ka bands are concerned. I had a problem with the Pro 78 very shortly after I bought it but Whistler exchanged it right away. Seems to work pretty well now. The blinking blue lights on top of the Pro 78 are cool.