Best way to see the city. Nice buying and paying ahead of time

We used Hop On Hop Off in Rotterdam, Copenhagen and Stockholm during our Queen Elizabeth Baltic Cruise. The port in Rotterdam is right on the 5 stop Hop On Hop Off route.
Bought tickets on line in advance in USD and so we we didn't waste time buying tickets during our limited time in port. Have done this all over Europe in past too because it offers not only a tour, but transportation if you are in a city multiple days. Rotterdam is small but got the overview and then went back to visit Market Hall before hopping back on to ship. Market Hall opens at noon on Sunday with lots of great shops, grocery in the basement no credit cards and one of the world's largest photographs on the ceiling. There was a flea market outside with more things for locals such as clothes, fresh vegetables etc. Maritime Museum and the Cubic Houses are right there. We didn't do the bike rental but it was an option.

There was major confusion as to the bus schedule, and we had to wait close to an hour. .Once we got going, the tour was good - as a matter of fact, we went around twice.

There was only one bus running in Rotterdam on Saturday morning April 23, 2016 instead of the every 30 minutes announcement in Viator Information, so we had to wait 45 minutes before the bus finally arrived at the Rotterdam Cruise terminal which is a windy space to wait outside.
We did the tour twice without getting off the bus, and noticed that the text spoken by a live commentator was adapted to the kind of guests aboard, the first round was spoken only in Dutch, the second tour was spoken in Dutch and English as some english speaking guests had entered the bus as well. The text lines were shorter on the second part, as he had to speak more in the two languages while passing by.
The commentator was witty, and the tour was more comfortable compared to other HoHo tours with systems and earphones where you can select the languages, but most of the times those systems just don't work flawless and you have to switch to other places to get a result at your EarPods.
The negative score is really due to the fact that Viator published wrong information about the half an hour cycle. If we had known it would have run just every hour, we had no need to stand outside to wait that long on a windy corner waiting for the bus. Got a hefty cold due to that which reduced my cruise pleasure afterwards as well. You better skip the Viator Offer and just buy your ticket at the HoHo bus as soon as you see it somewhere in town.

Long wait for bus to arrive at no time was there a mention of the free coffee as stated when booked

I purchased a trip and waited for the arrival of the HOHO which never arrived. Apparently the HoHo only operates on Weekends during the winter,,,,,,,something Viator should have known. Poor.