We enjoyed our time on the Segways. It was a great way to experience South Beach, and our tour guide pointed some nice fun-facts about the area we were in.
The reason for 4 stars and not 5 is because the tour started close to 45 minutes late, which made for a very stressful experience because it was only supposed to last for an hour and we had reservations for a different activity after this tour that we missed. The guides also asked for tips on three different occasions during an hour ride which seemed like a lot, and one of the guides kept vaping an e-cigarette while riding so it wasn't pleasant being next to her - but we just rode ahead to get closer to the other guide.
The Segways themselves seemed in good condition, and everyone in the group was able to get the hang of it pretty quickly. The cost of this tour was less than some others in town, so that was another positive.
If you are looking for a quick 1 hour tour around south beach I would consider this company, just make sure you don't make any immediate plans after the tour in case they run late again.