A nifty little summary of the strain on 3G networks: Carriers want the additional revenue, but networks are performing inconsistently around the country, as capacity in some markets hits the limits, Matt Richtel reports in the New York Times. Just putting in more cell base stations doesn't help, as it increase interference. Chips have to be smarter, carriers have to tune their networks, and, apparently, users just have to put up with it.
Not mentioned in the article, which focuses largely on AT&T's network, is that AT&T pushes Wi-Fi to its iPhone customers, which in turn provides a more predictable experience in urban areas indoors, while offloading traffic from the 3G network and reducing interference among active devices.
AT&T has foolishly opted to require iPhone users to request access at an AT&T hotspot through a cumbersome process. Instead, AT&T should push data from iPhones onto its Wi-Fi whenever possible, because the experience will certainly be comparable, and generally superior, given the backhaul AT&T has in its Wayport-acquired locations.