I have owned this car for about 2.5 years and have no significant problems with it so far.
I have had to replace brake light bulbs 4 times and the seat belt pusher has broken. The wheels get scraped easily. The remote/comfort entry works intermittently sometimes. Pretty minimal problems.
I replaced the tires with non run flat Cooper RS3-As with good results. It needs winter tires for deeper snow and if it's very cold though. Gas mileage isn't great especially in the winter, but the car performs so well, it's hard to complain too much.
I really hope there are no major problems with this car but it is getting old so it's something I have to prepare for. But so far, this car has been such a pleasure to drive and own. The radio is rather complicated and many things are not very intuitive. Being a rocket surgeon is helpful to own this car. Reading the manual is a must unless you're really smart.
But it drives so well, it's hard to argue with it's problems. If it starts to get really expensive to own it, well then it will have to go I guess. But so far, I really like it.