The promised update for iOS 4 that was expected to deliver more accurate displays of signal strength arrived today, and after some good old-fashioned TBWA*, I think it's safe to say the bars that represent the signal finally bear some relationship to reality. But all this release does is apply a cosmetic fix to a problem that never should have existed in the first place.
Before installing the update, I charged up the iPhone 3GS that I use for tests, and visited a few neighborhood landmarks near eWEEK's San Francisco offices to get an idea of how the bars were displayed with iOS 4; these were Yerba Buena Gardens, the Bike Messenger's Wall where Sansome and Sutter brush up against Market Street, and the Steps of Dropped Calls at 85 2nd Street. After having some lunch and installing the update, I headed out to revisit my sites.
Here's a pair of screenshots from Yerba Buena Gardens (37Ã‚Â° 47' 5.2944" N, 122Ã‚Â° 24' 10.3572" W), which I visited at the start of the "Before" circuit and at the end of "After":
I had five bars displayed at each of my locations during the "Before" phase, and only experienced problems when making calls from the steps of the building across the street. After the update, the only location displaying five bars was Sansome and Sutter; the others displayed two or three bars.
As I expected, calls made after the upgrade (in midafternoon) appeared to go through a little better than during my first round, which took place around midday. That's a reasonable difference in network congestion, all things considered.
So yes, if having meaningful displays of your phone's reception means anything to you, it's worth downloading another 378MB of software to your phone.
*Testing by Wandering Around