We did the trolley, and I sort of liked/disliked it. What I disliked was that it did seem like a little bit of a waste of time vs walking, and it took forever (20min+) to catch one mid-route. We seriously could have walked back faster if the employee working at that stop (it was one where they sold tix) had been more aware of where the trolleys currently were, or at least had been honest about it. He said it would be a few minutes, which it clearly was not. Anyway, ultimately it's about whether you want something cheap/fast (which walking would be) vs something informative. Ultimately, we were glad we did it (the adults anyway) only b/c the driver told us a lot about the history of Key West, flora/fauna, etc that we didn't know and pointed non-obvious but interesting things out along the route, beyond the bigger tourist attractions. If I went back, I wouldn't do it for the transportation aspect, but for a first time visit - it's worth it for the tour guide aspect.