You don't read much, do you?
"...and it has yet to drop calls..." it didn't drop them previously, either.
Obviously, the display has been tweaked, but since they increased the dynamic range of the displayed bars from -113 to -121, it doesn't lose the last bar - either way, it's just doing fine making and holding on calls with the single, last bar.
All I know is that iPhone 4 has been able to maintain / make calls in 2 areas in my region that have been known mobile death zones (they have been zero bar / no carrier zones since the days of my Nokia N73), and I am able to make / maintain calls in them with my iPhone 4.
What's particularly funny is that the only people whining on about iPhone 4, how crappy it is, and how terrible Apple is, are the same people who don't actually own one, have never held one, and have admitted to having no interest in the product.
Yeah, definitely a lot of credibility, there...
I have one (obviously) and so do a lot of my clients by now. Everyone is very happy and satisfied with their iPhone 4.
No, wait, one guy was pretty unhappy -- he wanted a white one, and had to settle for the black one.