In September 2006 I purchased a scooter. Mine is manufactured by TGB, a.k.a. Taiwan Golden Bee, and imported to the U.S. by Cobra Scooters in Morrow, GA. I purchased it from Twist 'n' Scoot, located slightly north of Piedmont Park in Midtown Atlanta.
I'm not sure what TGB calls this bike (it doesn't match anything displayed on their website) but Cobra rebrands it as a Sunset.
Engine: 49.3cc two-stroke 1-cylinder, air-cooled; 4.9 HP @ 7,500 rpm
The advantage to this engine is that in the state of Georgia, any two-wheeled vehicle with an engine smaller than 50cc is classified as a scooter, not a motorcycle, with reduced requirements: you don't need a motorcycle license, vehicle plates, or insurance. The tradeoff is that you can't legally drive it on highways (which wouldn't be a good idea anyway).
Typical speed for my bike is about 40 m.p.h. on flat ground with just me on it. Downhill is faster (I've hit 60 at times) and uphill can be much slower. I average from 60 to 70 miles per gallon, depending on how aggressively I drive.
I live about 10 miles from school; taking the car on the highway is about a 20 minute trip, door to door. On the scooter, I have to take surface streets the whole way, but the route is a little more direct. If traffic cooperates, I can make the trip in 25 minutes. The reality, though, is that it often takes 35 minutes or more.
The Parking Department does set aside spaces for motorcycles and scooters, and requires you to register for these spots. If you have a permit for a car, registering your bike is just a couple dollars more. If you just want the motorcycle permit, I believe you have to pay full price.
(On the other hand, I've never seen someone get stopped/ticketed for riding a scooter on walkways or parking not in a space/without a permit.)