Right now on the Apple discussion forums, there is a thread going on about the built in speaker volume. Many many people including myself have a problem with the built in speaker volume, we can barely hear it. This includes when a call comes in, listening to a caller on speaker phone, listening to music and videos and timer alarms. In short, for many of us the speaker volume just plain sucks.
I can hear all sound perfectly through the earpiece, that was never a problem, it's just when trying to listen with the built in speaker.
The complaints have been about the speaker phone, NOT the ear piece. The ear piece is perfectly fine. The speaker phone is fine in a quiet room, but it doesn't work too well if theres a fair amount of noise around.
Reception on my iPhone has been just as good as it was with my old cell phone.