FHSS and 802.11b/g/n not friends
802.11 FHSS (frequency hopping spread spectrum) wireless LANs have become mostly obsolete; however, you still find them supporting older applications. The problem is that FHSS, which occupies the entire 2.4 GHz band, causes significant interference to 802.11b/g signals, which only occupy approximately one third of the 2.4 GHz band. It doesn't matter what you select, FHSS takes a toll on 802.11b/g/n (and not vice versa). This has become an issue with a hospital that I'm currently working with - they have an existing FHSS network supporting an important physician communications system, and they want to install 802.11n network to support a new wireless application. So, be sure to carefully survey for the presence of FHSS networks.