I am now on my third v551 in a single year. The battery was not as much problem as the reception for inside building use, my first one was working great for 3-4 months and then it will start to loose signal. Sometimes I will get not even a single bar at my own house. Cingular did signal check to see why I was not getting signal and told me that the v551 should get medium coverage in my area.
Pretty soon the signal will drop whenever I get to my house and disappeared completely. I've got a replacement phone from Cingular Mail in program.
The second v551 works for 3 weeks and starting to shut itself down. The screen will go black and at first I was able to use the power button to turn it off and on again but the third week it will shut itself off three or four times a day.. So there I go to Mail-in replacement again (it is still in warranty), this time I told them to please check the phone before sending it to me before I don't want to deal with it anymore. The lady on the phone said that the phone comes from a different location (and i think they are refurbished phones) and she had no control over what I am going to get.
Meanwhile I had to take out my sim card and use it in a borrowed phone so that my work could contact me. So wish me luck third one might be a charm...