My little grubee skyhawk 66cc can get up to around 35 but it feels like it's gonna come apart beneath me when I do it, so I don't go that fast for long (it's illegal to go that fast out here on a motorized bike anyway). She likes to putt along at 20mph all day long however.
I'm thinking about taking the scooter plunge myself. I need something that goes a little quicker than the motorized bicycle and won't beat me up on my 35 mile commute. Right now I'm riding it to a secure (enough) location and hopping the bus, which doesn't solve the problem of infrequent, unreliable bus service here.