Electric will bring you grief. Affordable battery technology is not there yet.
You are economically safest with a Honda, Genuine, or Yamaha. If you are just buzzing around town, the Honda Ruckus is a best choice. There is a plenthora of aftermarket parts for it because it is so popular. You can sometimes practically steal them on ebay sometimes.
There are website forums just for the Ruckus. Battlescooter has lots of upgrades. You can lower the seat, stretch the frame, add footpegs, crash bars, racks, bigger engine, etc. The scoot is great off the floor, but if you want to trick it out later, the possibilities are incredible.
The Yamaha Zuma 50, and 125 are great bikes.
The Genuine 110 Rattler is getting great reviews. Genuine is an American company, producing high quality scoots.
Vespa costs too much for what it is. Its good, but costs too much. Sort of like buying a BMW when all you needed was a Toyota.
Look at the Honda, Yamaha, and Genuine scoots. They won't let you down.