I'll be the first to comment that I definitely agree with your statement. I was in a really busy NYC Apple Store last night (SoHo for those keeping score at home) and was walking my mom and dad through setting up her first iPhone (4S). It was very clear, I was able to hear everything they said almost in a way like I was in a quiet room. Very impressed.
And the call clarity overall was much improved with no sporadic drop-outs like I had experienced before. I rarely talk on the phone, but this is just one more feature I appreciate!