We've put 150k miles on the car since it was new and have had a good experience overall. Good gas mileage, comfortable, and swallows a lot of luggage for a car this size. Problems have been the usual complaints for these cars - arm rest broke at 100k, cup holder jammed, and many headlight bulbs. I've gotten really good at replacing them. No major problems. Currently have an intermittent starting problem that our local dealer doen't seem to be able to fix. I usually won't buy a car the first year it's made but this one fit our requirements so closely I decided to go ahead. A few early problems but a couple of software updates and it settled down. Good service, good car.
Carries a ton of stuff in trunk with the seats down it will carry an even larger load. Looks good, attractive stying. Reasonable acceleration and handling for this class of car.
The newer S40's seem to have fixes for most of the most troubling issues. The dash needed a new layout. The headlights burning out also needed to be addressed.