I ride a Raleigh Gruv 2.0 with a 32cc two stroke motor kit. It only gets 132 mpg at this time. The company said it would get 160-180 mpg. Perhaps when it is fully broken in the mileage will improve.
The top speed is about 27 mph on level ground without any wind. The motor kit weighs under 14 pounds. The bicycle can be parked anywhere and it is light enough to be carried up stairs and stored on my apartment balcony.
It can be pedaled without the motor running which makes it stealthy around crowds of people and police at public outdoor events. If it runs out of fuel it can be pedaled to the nearest gas station.
About the Honda Ruckus; it will be OK for speeds below 40 mph. I owned a Metropolitan scooter with the same motor. It will go 39 mph when new but as it gets older it will go slower. I sold mine with 8000 miles on it. By then its top speed was only 36 mph and the fuel mileage had dropped from a high of 100 when new to 88 when it was sold.
Honda and the other Japanese motorcycle companies make great commuter scooters in the 150 cc range, they just don't sell them in the USA. They also make great commuter motorcycles for Europe.
I owned a Kawasaki 500 LTD Vulcan cruiser. It will smoke the Honda VLX 600 and most 800cc cruisers. It is way more comfortable and cheaper to maintain because it has an inline engine. I intend to buy another motorcycle some day. I like the smaller cruisers. If Kawasaki would get rid of the black color of the current Vulcan 500 LTD I would like another one of those. They get 54-56 mpg. A Suzuki S40 (652cc single) cruiser is slow but gets 61 mpg.
Cars are so much more comfortable than motorcycles, but when I ride inside a car I don't feel as safe (except on icy roads). I'm always fearful of bumping into something or having someone else bump into me. I don't feel that at all on a motorcycle.
I would buy a Genuine Buddy or an Argo scooter if there were any local dealers. Alas there are none. Anyone buying a new Vespa or Piaggio better have access to a dealer or have good electrical mechanical skills.