Good overview of the city and commentary interesting. Most drivers friendly and offered extra information to help us - e.g. times of last buses. However, our first driver did not stop at one of the stops we wanted to alight at he claimed there was no one waiting at the stop...but he had stopped at all the other stops despite no one being there! He did drive back for us and let us get off, but it wasn't a very positive experience
I had an unpleasant experience with the driver. He challenged issuing tickets as we had bought it from viator. He insisted that we should have bought it from their company website and went on and on about his company wont get money in a quite patronising manner. This was a bad start to our trip.
Apart from this incident, the prices on viator are quite competitive and i had a pleasant experience with the purchase process on the website.
The tour information was excellent and the trip around Cambridge was fun and enjoyable. Would definitely recommend. Only downside was that our tickets stated that the buses stop running around 4.30pm, which was really early for the hop on hop off experience as we were doing a day trip. So do check!