I can only speak from my personal experience, but the RS 800 MHz antenna works very well in my location (central Phoenix), and allows me to hear everything that I want to hear. Most of our city services (including PD) are on an 800 MHz trunking system, and they come through crystal clear with amazing sounding audio. Our local fire department is still using the 154 MHz frequency range, however, but I am also able to receive their communications with excellent results. The state police (DPS) are at around 460 MHz and, once again, I get clear signals with full quieting. All with just the 800 MHz antenna. I might also add that I receive a surprising amount of "fringe area" communications with the same setup. A little static-y, but still with readable signals from some of our more distant adjacent communities.
I can only guess that by using the 800 MHz antenna, I am avoiding the supposed front-end overload that many others have complained about with the newer GRE-built radios, while enjoying the benefits of my new radio's acute sensitivity. Whatever it is, it works for me. Your mileage may vary, of course...
Rodney