I just purchased my first digital HDTV and am VERY happy with the picture quality using an antenna to receive over-the-air broadcasts. I read one review of the TV I purchased that mentioned it changes channels rapidly. My question is what speed is considered "rapid" versus "average" when changing from one digital channel to another? [I set my TV's tuner to only receive the digital channels.] My TV sometimes requires a couple of seconds and sometimes is much faster. Thanks.