This car tends to be pitched as an Audi/BMW alternative by much of the motoring press. I can see why, the build quality is excellent, but for me there is no contest in this 3 way comparison; it's well known that the BMW 3 Series is a superb machine, but unfortunately it gained a reputation as being a bit of a berk mobile, being regularly spotted cutting people up and tailgating on the motorways with a general "get out of my way, I own the road" kind of stigma. It seems like the Audi A4 / A3 and VW Golf are now taking over this role, maybe the Beemer will lose its stigma if all the berks switch to VW/Audi ownership.
The S40, while in my opinion being very nearly as good as the Beemer and the Audi, doesn't suffer this reputation, you can still run around in a quality car, AND be let out at junctions by other motorists.
The interior is a pleasant place to be, quality plastics and a clean and tidy layout, the floating centre console is a work of art, seats are the best available, very comfortable on long journeys.
The Ford/PSA diesel engine is a touch noisy, but is very gutsy and returns 50 to the gallon as an average.
The dealer is brilliant, very very helpful, servicing is reasonable, but I nearly fell over backwards when I got a quote for new tyres; avoid the 17 inch wheels, they look great but you need to re-mortgage the house to change the tyres.