I've had good luck with my Rad Mini, have a couple hundred miles on it so far. I basically use it for round trips 10 miles and under, and it's performed great, The Rad Runner Plus is the standard model with all the accessories it has the 20 in. tires like the mini but it doesn't fold. I had to adjust some of the bicycle stuff on it out of the box (brake, derailleur), but the electronics have been very reliable.
The Rad Runner is a fat tire and rides as such. All in all for the money I like it. If I were to get another one it would be the City, I think the ride quality on pavement would be smooth. I think they have nice standard features, the lighting system is good with a brake light, the screen has good info and is backlit at night, motor cut-offs on brakes is a good thing.