This is definitely worth getting to see the sites in Porto, we bought this for 40 euros for two days, there is no way you can do it in 1 day, this stops of at several stops, and you can pick up from any stop, there is some really lovely architecture, beaches, zoo, churches, sea life, to name just a few.

I did this and the Grayline red bus tour, This was better but neither provider is as good as Madrid Spain (for example) Hop on Hop. The most frustration is locations of stops does not give exact addresses for the locations, Someimes they are very general

We used all the options that we had purchased and found the tours overall very good. One negative was that the time between the buses (officially 30 minutes, but depending on the traffic sometimes longer) was too long and there was no timetable at the stops. Riding on the old tram was particulary good, although on the way out to the coast, the tram was so full that I couldn’t actually see very much. One word of warning, I am quite small and also have arthritis in my knees plus a new hip! Getting in and out of the tram was quite difficult as the steps are quite steep. Maybe for most not a problem, but for me a hurdle.