hop on hop off

There are two types of hop on and hop off bus. One is the lopen tour ( the yellow and green) and the other one i don%26#39;t know what it is called but it is red. Which one is better?

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http://www.paris-opentour.com/index_eng.htm

http://www.carsrouges.com/uk/index.html

Compare the routes, number of stops, overall area covered and the prices...