Of the two tour companies operating in Valencia this one, with the green buses, has the better commentary and the better vehicles for taking photos from as they don't have windows.
However the frequency is a lot lower than the other companies
Two tours operate a Historic tour that focuses on the city centre and west of the city, taking in all the major sites
The second tour takes in the Marina area and the west of the city centre
Pre-recorded multi-lingual commentary tells you about the key sites and some of the history of the city