My mother and I usually do a hop on hop off tour when we travel throughout Europe as she has difficulty in walking long distance. Also, this is the ideal way of seeing the highlights of a city without having to figure out the local transportation. The only complaint was the wait on first stop for those that had to purchase their tickets. It is a convenient and economical way to see everything on your wish list.
We arrived on a cruise ship and when we went to get on the bus at the crusie ship terminal they told us we needed to buy another pass (we were unaware of this) to get from the cruise ship to Stockholm but they couldn't take our money because of an arrangement with the cruise ship. So we would have been out of luck or had to take a taxi for $150 to get to Stockholm. We argued our way on to the bus and it was the same on the return trip - had to argue to get a ride and not be abandoned in Stockholm. In Stockholm there were not enough buses with huge lines waiting at each stop. The Boat to ride was short and just toured around the small bay. The Canal and Bridges water tour would have been a better choice but we did not know about it as an option.
Was really surprised when we got off ship at Nynashamn and showed our Viator voucher and told I did not have to pay anything else to get to Stockholm. Took 45 minutes to get to Stockholm but they had 4 buses at port ready to pick up passengers. They started bringing us back earlier than the initial suggested time of 4PM (actually was before 3PM) The boat tour was fun and nice views of city and bus routes took you to many of major attractions. Many on first bus rode it over to ABBA museum and were able to have tour without much wait. Bus tour is on Red Buses.
The bus and boat go to the big spots. There is very little commentary on the headsets. The employees will not answer questions fully or at all. Even basic questions like is this bus going to make any other stops, are you driving to the extra ship stops, where is the closest stop. The other company goes to the same places and may have better customer service. I don’t know.