Not too many of my friends have smart phones (other than the iphone at least) so I don't know how the 3GS compares to them, but compared to dumb phones, my 3GS usually loses hands down. My parents house is right on the edge of 3G service, and my 3GS sometimes picks it up, but then it gets caught in the never-ending 3G>EDGE>3G>EDGE loop that renders the phone useless. My brother's Sony Ericsson dumb phone gets perfect 3G in the area.
So, in short, I'm looking forward to the improved antenna design. Plus, it's one more feature to show off on my cool new gadget 😀