Tried a couple of month ago a Piaggio 3-wheeler.
First impression was very steady, lots of power compared to my Grand Dink 150, but driving it during heavy traffic was then a different story. Have to say, drove only about 15 minutes and did not feel secure, particular in tight left turns. One might get used to in no time, but the price, even for that used one, way too high. If I could get hands on a wrecked one, just to tinker, yes, but to ride it instead my scoot, no.