Bill - as already stated, the 5GHz supports more channels, which should help with co-channel interference related issues - assuming your devices support 5GHz. Unless you want a drawn out explanation of band steering, the client will determine the radio. Unless you are near an airport, military facility, or Dopler - use the DFS channels on the 5GHz and 20MHz sub channels. Other than that - given that most of your traffic is going to be North Bound - the limiting factor will be your Internet Service Provider.