My opinion is that a lot of the smallest outboards are unnecessarily noisy, unreliable, rough running, and difficult to operate because of their design.
When possible get an engine that has:
1. two cylinders; they're much smoother than just one.
2. water cooled; it runs cooler to the touch, and is usually a more sophisticated, purpose-built engine, not an adaptation of a lawnmower, generator, weed-whacker, chainsaw, or other type of engine.
3. has a F-N-R gearshift, or at least a F-N set up; they're much easier to maneuver with than a direct drive, or even a centrifugal clutch system.
4. is light enough to handle easily; the older non-EPA compliant 2-cycle ones are lighter than the newer 4 strokes, but it's a tough trade-off, and you have to mix the gas and oil, etc. As one gets older, a 34 lb outboard looks increasingly better than a 47 lb one.
5. another nice feature is to have a motor that will run off either it's internal gas tank or an external one, especially if you're going to use it both on a dinghy and as a kicker motor.
That would be my shopping list, along with some research into the history of the reliability, repair record, and parts availability of any motor I was considering.
Joe. :teeth :thup