Funny that...
... I have a Sony Ericsson phone (on 3 network) that seldom has a signal, and when it does it's very weak. It also crashes regularly (probably due to lack of signal) and drops calls, even when it does have a signal. I'm in dispute with 3 at the moment about it has I have had one replacement and two repairs, and the damn thing still won't work properly. I will never again get a Sony Ericsson, and will never again get a contract phone on 3.