This Server Fault blog post shows some tools you can use to view interference on your wireless network: blog.serverfault.com/2012/01/05/a-studied-approach-at-wifi-part-2/. They mention Vistumbler, which only works on PC's. Is there a similar tool I can use to measure wireless interference on a Mac?
Also, is it better to be on a channel with many AP's, each with a weak signal, or on a channel with only a few AP's, but a strong signal?