[pdelbarba]

I've used both marine (FM) and airband (AM) radios. My marine experience was in a relatively uncluttered environment (Cleveland) so take this with a grain of salt but I found that you rarely had people talking over each other in that environment, especially with it's limited propagation. Airband on the other hand is almost always a very high radio traffic environment if you are actively switching between tower, departure and center channels throughout the flight. It becomes imperative to be able to tell when someone stepped on ATC and you didn't get some message.