I used to own a 2008 Scion xB and I would usually fill up every 6 days. My commute has not changed since buying the Tucson (neither has the size of the fuel tank as it is the same as my old Scion.) Now I fill up every 7 to 9 days depending.
If the ride seems rough at first, ask the dealership to check the tires. When they come off that truck, the tire are usually over inflated to avoid flat spots on the tires during transport. This makes a hell of a difference.
I never cared for the Tuscon before the new style came out. The first time I saw one roll off the truck, I fell in love! Very sleek. Reminds me of the Lexus RX.