A FW of the same length as a TT will seem bigger, due to the vaulted ceilings in the lower portion. But IMO you get more floorplan options in TT. Most FW are designed for 2 people without kids, although recently I have seen some FW with bunks. In a FW, the bathroom is almost always on the upper level adjacent to the master bedroom.
While others have mentioned the additional cost of the higher frame of the FW, I also think that FW are set at a higher pricepoint because of the type of users they sell to.