The tour itself was very good. It packed in a lot and the driver was very entertaining. They were also very accommodating and friendly which we really appreciated.
The only issue was that the two seats in the back row on the right side (when seated) don't have working seat belts, which feels pretty dangerous given it's an open top bus. Once that's fixed, I would have no hesitation in rating this 5 stars but in the meanwhile, I'd advise arriving early enough to avoid those seats.
And if you end up with no choice but to use them then consider asking for your money back instead of taking the risk. This might be the quickest way for them to fix it.
Also - be sure to check the weather and keep in mind that with any wind from driving that it'll be especially cold if you're visiting right now, so wrap up heavily.