Sometimes if I am in an area that has WiFi, my 3G access sort of just stalls out. If I disable Wifi it is back to being fast. It's almost like my phone is trying to connect on the Wifi signals when I haven't actually connected it to any of the unknown networks in the area. So instead of ignoring those wifi networks and just sticking with 3g, it fails my 3g data connection. This doesn't happen all the time though. Phone calls always still work though. The screen still shows 3G and full bars, but 3G just goes out to lunch until I disable Wifi. For example checking an email I'll just get the animated waiting icon up top and nothing happens, just wait and wait. Disable wifi and all is good. Annoying.