How exactly does this pass work? You purchase a pass for 2,4 or 6 days, and it begins when you visit the first attraction. Do you swipe the card like a credit card? How will the museums know if you are on day one, six or have an expired pass? With the Paris Pass, they include a Metro as part of the package. Do you use the same card or do they give you a card that will open the Metro gates? Do you have to swipe the card again to exit, like in Atlanta on the Marta? You can visit the same attraction more than once as long as it is within your card time limit. I think that the Big Bus is only for a single day regardless of the life of the pass. On the website they say you can buy it and have it sent to your home, but you can also buy at CDG without the mailing cost. My arrival date will not be my first use anyway, as I never plan anything on arrival or departure dates just get acquainted with the area around the hotel.
For the ones who have used either pass in the past on average how many days have you bought and how many do you take in a day.