I have had my RX65 for about 3 weeks now, and I am very impressed so far. I had a Whistler Pro 58 for about 5 months before I got the Bel, and a Radio Shack POS for several years before that. I chose the RX65 because everything I researched about the "big 3" said that the RX65 has the best range and sensitivity without too much falsing.
It definitely has good range, but I have only had 1 LEO encounter so far (Ka). What impresses me the most is the increased filtering capability. I drive in the same areas a lot and I would get X and K falses like clockwork in certain areas. With the RX65, it has filtered out about 80% of the K and X falses that I normally saw.
I ran with X band disabled for the first 2 weeks, because I am 95% sure that the LEOs in my area do not use it (PD use K and CHP use Ka). Since I was getting such good results with K band filtering, I decided to turn X back on to see if there was improvement there too. There definitely is! There are still a few falses, but not nearly as much as with the other detectors.
I have not had a Ka false yet, and I have POP on! No POP falses either.
The only thing I would like to see from Bel in the next firmware for the RX65, is a City mode for K. I don't want the sensitivity lowered, but maybe a visual alert but no audible alert until 3/9 or so. There are just too many automatic doors now that use K band. At least give us the option of having K in a highway sensitivity or a city sensitivity.
I have tried having Ku and SWS on, but I have not had a SWS message yet (does that work anywhere in the US?) and I have not had a Ku false. Good to know that I already have the ability to use Ku if it does end up coming to my area.