Well, it really depends on the antenna system, regardless of what kind of radio you have it connected to. I'll use my two primary scanners for instance - the PRO-96 and the PRO-2096. Essentially the same radio but in a different package. I use a comparable antenna system for 800 MHz (really the only thing I listen to on either) for both radios.
The 96 has an RS 800 MHz rubber duck, and the 2096 has a GRE 90° angle 800 MHz rubber duck. Both receive comparably. The difference comes in sheilding and audio quality. I experience much better shielding from local RFI with my 2096 than with my 96. My cell phone barely gets into the 2096 from less than a foot away, whereas it is clearly audible through the 96's speaker from several feet away. The 2096 also has a larger cabinet and larger speaker, so the sound quality is much better, more like that of a commercial radio than a cheap scanner. Audio on the 96 is good, but on the 2096 its great!