In reading reviews on this car I never found a single professional review on the base model 4 cylinder. Only the $26K SEL with the V6. So I hope this helps.
I was looking for a good commuter car that was of reasonable size that I could put my 5 member family in it when needed.
I bought the basic fusion I4 S The only two options I got were the 5 spd automatic and the safety package (side curtain airbags).
For reference, I had been driving a 96 VW jetta 2.0l with 5speed. Most anything has to be better than that coffin... ahhhhh car. Someone hit the self destruct button on that car when it hit 100k. I was tired of spending 200-300 bucks every other month on parts.....
The things I wanted out of a car were a balance of good fuel mileage, comfort, safety and price. In other words I wanted a decent size car that gave me good mileage and wouldn't get crushed by a honda civic. I also didn't want to spend a lot of money since I drive a lot of miles.
I believe I have what I was looking for in the Fusion.
Comfort - I am pretty big guy. At 6'2" and 230 lbs I have been very comfortable on my 55 mile (each way) commute. I love the upright seating position, leg room, head room, shoulder room and the lateral support in the seats.
I have three kids. 11, 9 and three. One of them is in a car seat and they have plenty of shoulder room in the back seat. An impossible concept in the Jetta.
Fuel Mileage - I have about 1000 miles on the car and have gotten about 28mpg combined city and highway. I have a bit of a heavy foot. About 400 of those miles were city/back road. I typically roll along with traffic at 70-75mph and have some stop and go traffic in the city. I expect to see about 30 mpg highway at those speeds with more highway driving. Not bad for a true 5 seater (2 adults 3 kids)
Safety - Again, I wanted a decent size car. The jetta was too small and there was no Focus, cobalt, corrolla or civic in my future. I also have the side curtain airbags which I see as a big plus. Again, I have three kids. The impact ratings for all crash tests were Good. That is pretty common in this class of sedan. If you want Excellent, it just cost money to go bigger.
Price - The MSRP was 19,215. I paid 16,695 after rebates and incentives. That was $1000 matching down payment, 500 college student rebate and dealer discounting. I thought that was pretty reasonable for a new good size car with a lot of standard features.
Miscellaneous Pros - The styling is very nice. In my opinion it beats the heck out of the sterile looks of the malibu, camary, accord or sonata. The car has a lot of standard features (a/c, PW, P locks, cruise, intermittent wipers and CD.) The ride and handling are better than expected. Congrats to the Mazda engineers who designed the chassis. I love the visibility in the car except out the back window, but that is the price you pay for the higher seating position in the rear seats (i.e. more rear leg room) and the high trunk lid with the vast expanse of space beneath it. (i.e. Shut up and don't complain when you trade a minor item for two very valuable ones.) HUGE trunk!!!! Fold down rear seats. The doors close very nicely. One thing I found in other cars was the tinny cheap sound of the doors closing.... a lot like something made by GM in the 80's.
cons - the 4 cylinder and 5 speed auto are sufficient power, but the transmission is a bit lazy in selecting the lower gears. This results in the feeling that the car is "under powered", but it really just needs to drop a gear sooner than it does. I notice it the most during stop and go traffic and on back roads. Not that big a deal....but keep in mind that my other vehicle is a Chevy Suburban with all the power I could want. The fit and finish of the car is good, but it doesn't scream "good industrial design". The quality if the materials is fine, but just fine. The surface texture of the dash and trim is Blah. The radio albeit the base S model is just a square box dropped in a trapezoidal space. These features have "rental fleet" written all over them, but if I wanted a lot more I would be driving a new STS.
Overall I love the car. It is exactly what I was looking for. There are a few negatives, but keep in mind I was not looking for a race car that let had the comfort styling and quality of a rolls royce. I wanted to get from Point A to Point B affordably, comfortably and safely.
I hope this helps.