We have not done the ones you mention, but did one in Munich while waiting for our son to join us from his semester abroad in Italy. Well, our trip ended that day, as DH swerved to avoid a young woman who stepped in front of him, and he broke his leg. An ER trip, 6 days in the hospital, surgery, a nail and 5 screws in his leg later, we went home.
Segways are awesome, but pay attention to the training they give you to ride them. Then, follow it! That said, up to the point DH broke his leg, we had a fantastic time and saw a lot of Munich!