I was in Charlotte NC. all weekend and this was my first time with 4g. Very impressive speed when the phone was not locking up. I could switch to 3g and problems seemed to go away. I was using Google maps with navigation and at times it would just freeze the phone completely up. Very frustrating. Drove back to Knoxville (home) and all seems ok now. I hope when Knoxville gets 4g its not like what I experienced in Charlotte.