One thing to note about MyWifiCoverage and RadioMobile -- they're basically the same thing underneath. RadioMobile is the free product. It's incredibly powerful, but takes some time to learn and to get the settings right for your application. MyWifiCoverage is the new pay-to-use version by the same author. It is easier to use, but can get expensive for a large network. It doesn't necessarily create a more accurate map, though, since it uses the same underlying mechanisms, which are based on the Longley-Rice propagation model and the SRTM topo mapping data.
Credit to Roger, though, for doing this all for free for so many years, only recently trying to really monetize it, in partnership with another supporter of the WISP community.