We bought our 2006 Fusion used as a 3rd vehicle. It had 18,000 miles on it at the time of purchase. It has proven so flawless and so much fun to drive that we are using it far more than our other vehicles. The fuel mileage is incredible. In driving that is typically 75% highway and 25% city it never gets less than 29 mpg, and on trips at 65mph it averages between 34 and 38 mpg. The interior is roomy and very comfortable, and the ride and handling are excellent. I highly recommend it. Not a single problem at 36,000 miles now. I did replace the driver's side door handle, but this is a $40 part and only takes about 15 minutes to replace with very few tools.
I love the styling, the interior layout and the storage compartment on top of the dash. It also has a smooth ride and handles very well for a family sedan. The I-4 has ample power for merging and passing.
None. You can't improve on perfection. Our next new car will be a Fusion.