This is a great way to see a new city on the cheap. I ended up taking the tour during the day, but I can only imagine how beautiful the trip would have been at night, as well.
The tour guides are upbeat, energetic , and knowledgeable. Since it was 115 degrees outside when I rode the bus, the guides would periodically spray everyone on the open-top with water. Never in my life would I have asked to be sprayed with water. Never say never, because being sprayed is a lifesaver when riding on top.
As many times I visited Vegas, I never went downtown, so the bus trip was really an eyeopener for me. I am now inspired to take the Open-Top tour in Washington DC!