I personally prefer to use the KTTW card with charging priviledges. That's just me. I like doing it because it keeps all of my charges together, on the last day you get a complete list of all of the charges, and you can go to the front desk to verify if you think something is wrong. I must add, though, since you can use the card through midnight on the last day, that will come up as a second (or 2nd and 3rd) charge.