Me! Me, Teacher! I know the answer!
I've got a Tanaka:
and love it. You can see how much smaller it is than the motor it replaced. Noisy little bugger, like a little chain saw, but it does fine with a small boat like a DS.
Speed is fine. I've never measured it, but for getting around it's okay. I would imagine it's close to hull speed. If you're dealing with a river or tides or huge winds, you might have problem, but for most normal Daysailer adventures it's great.
It's so much easier to throw it in the car, on the boat, back to the garage. It's ridiculously light.
Carlos