Those Briggs & Stratton outboards are essentially lawn mower motors as they are air cooled instead of water cooled. I do not have much experience with them, however I did do some research on them a few months ago as I was looking for a smaller affordable outboard. From the research I did, some people loved them, others did not--but it seemed like the most common complaint I read about them wasn't that they overheat, or that they lack power--but rather the sound. They sound like a lawn mower and not an outboard. Where I think they would be beneficial is in swamps or really murky water. Since it does not have an impeller, it doesn't hurt it to run it out of the water, or just skimming the surface.
As far as how it would compare to a typical 4 stroke liquid cooled motor power and longevity wise--I don't know. I would however tend to avoid running it WOT for long periods of times on hot days--air cooled scares me!
