You stated that you have three bars, does it also say 3G You may have a voice signal on extended network, but what about 3G. Also if you search you will see a way to add a percentage of signal with the bars. I cant remember exactly how but I saw it on here.
I usually travel alot. Usually when I get to a destination, I do the *228 option 2, just to make sure I am good where ever I am not sure it makes a difference, but gives me something to do while waiting to get of the airplane.
Crisp clear, and muc better signal. I am visiting family out of state and normally have to stand in one place to make phone calls here. Now I can wonder the hole house. Only difference is changing from BB to iPhone.