In earlier versions of Android there was an option to toggle data between 2G, 3G preferred and 3G only. After the ICS 4.0.3 update for Nexus S, there is no option for "3G only". Did Google lock down ...
My UK Nexus S (Android 2.3.2) has real problems sustaining a reliable data connection on 3G even when I have a full signal in London. Connections time out or pages/tweets/whatever load exceptionally ...