3 - You really need to test an F Sport to make your own mind up. Personally I find the F Sport a little too hard for my liking, but I put up with it for the looks and the paint colour :)
A Premier, also on 18" wheels, is a little softer due to the different suspension, and the 17" wheel models are noticeably smoother in their ride without being too soft.
Economy on the F Sport is a few mpg less than the other models due to less efficient aerodynamics.