Well I think it all boils down to is this a software issue that Apple can correct or is it a hardware design flaw as some RF engineers have said as in the PC Mag article.
There is a report out now that Apple maybe releasing an update as early as Monday that will correct these problems! Hope it is true, I initially felt this was a software issue, but so many others have have done testing that seem to indicate otherwise. I sometimes wish I knew more about this kind of stuff. Thing is no one knows enough about the design that Apple is using for this stuff, so all this testing is really meaningless, though we've had fun doing it. I guess we'll see when Apple drops their iOS4.01. The thing is you could make an argument either way!
Here is from an Apple Insider Report:
Software fix in the works
The fix is expected to address a issue in iOS 4 related to radio frequency calibration of the baseband. Readers who saw the original forum discussions say that the issue is believed to occur when switching frequencies; because the lag is allegedly not calibrated correctly, it results in the device reporting "no service" rather than switching to the frequency with the best signal to noise ratio.
iOS 4 introduced some enhancements to how the baseband selects which frequencies to use, so it makes sense that the error may have crept into those changes. Additionally, this explains why iOS 4 has also caused similar problems for iPhone 3GS users.
AppleInsider | Death Grip hysteria may end Monday with iOS 4.01