Other problems with signal
Google have also acknowledged that this is specific to certain areas of T-Mobile coverage, and is somehow related to the T-Mobile network. I've not heard any reports of this problem from the 10 or so people I know with Nexuses in the UK.
But it's not just 3G that has problems with Android. There's a known issue with Android where it loses signal and then fails to re-aquire it, requiring the owner to switch Airplane mode on and off again to get a signal again (not just 3G - this is a phone signal *at all*). The issue was present in 1.5, but remains unresolved in 1.6, 2.0 and 2.1 by all accounts, and is not hardware-specific:
Having said that, new hardware (and software) has bugs. People want pocket computers that do everything, and they want them to take huge leaps in functionality and hardware every 6 months. It's hardly surprising there's going to be a few glitches.