I am a new convert from the iPhone and couldn't be happier. I have one problem I cannot figure out. While at work my phone freezes and locks up 2-3x a day. I have to press and hold the power button for 15 seconds to reboot. Also, while at work, the phone keeps asking me for my SIM PIN. I haven't had any problems at home or other locations.
I have a Galaxy S which I bought from a German on-line retailer. I am in Germany and use T-Mobile. My colleague also has the same phone, however, he bought his from O2 and uses their network. I compared firmware versions and they are similar, however, his has a slightly different name. We think it is an O2 specific release. He has not experienced any problems.
My running theory is that this has something to do with the network. Maybe I am having connection problems.