The most bizarre things go wrong with this car. Mostly electrical gremlins, which seem to be a sore spot for these cars. This specific car was built during the very first months after the model was introduced, and BMW apparently ironed out most of the issues I had.
They include: speakers cutting in and out, the lights on the head unit getting incredibly bright and then fading out by themselves, pixels that faint (they seem to die but come back a few days later) and sometimes, the tape deck eats cassettes and won't eject it. You must play with the eject button and power button until it ejects the tape (or rather, an iPod tape adapter) but afterward, all of the sound settings have reset themselves (BASS 0, FAD 0, BAL =).
The paint on the car is delaminating, but again, it's a 15 year old car, I'm not the only owner, so I cannot blame the car itself.
Purchasing a car with over 100,000 miles, I knew I was inheriting other people's problems. Mechanically, the car runs fine. I change the oil every 5,000 miles and always use at least 89 octane rated gasoline.
That being said, the transmission seems a bit clunky (it is the 4 speed auto, which was upgraded later to a 5 speed auto, which is supposedly smoother).
Sometimes the car idles rough, but that goes away.
Many interior surfaces (grab arms on the doors, center console pull) are coated in soft touch spray paint. It has worn away tremendously from when it was new. I don't know what the previous owners did to this poor car, because I have never marred the surface.
While I have noted there are a lot of little issues with the car, overall I am incredibly satisfied. I have never been stranded by the car. And while dealer service isn't the best (I understand I drive a 15 year old car and I'm not their *top* priority), I have only had to deal with a dealer twice.
The seats are comfortable and heated. I am so used to also having a heated steering wheel now, that I don't think I could ever own a car without one.
The car is a joy to drive in the snow. I had a car dealer tell me himself that these cars do not handle the snow well. But with all season tires and the ASC (automatic stability control) I haven't had a problem in less than 2 inches of snow. If you can't drive through it, you shouldn't be on the road.
I frequently drive other people around, and 4 people fit in unabashed comfort. Five fit in a pinch. The car is vault-quiet and controlled.
For its age, it has a bunch of fun party tricks. One is the comfort key, where you can put all the windows down and open the sunroof with the remote and up with the key in the driver's door. Another is the side view mirror, which tilts down when the car is in reverse. There is an automatic cruise control button on the dashboard that you can set to a predetermined speed for a quick-set cruise control. The center armrest slides fore and aft, as does the (HEATED!) steering wheel. BMW also uses lighting that is low interference, so if your passenger turns on a map light at night, you won't be blinded. The glove compartment light doubles as a rechargeable flashlight. Not too shabby for its age.
Ride and handling balance are great. The car doesn't look its age at all, in my opinion, because the proportions of the car are so balanced and timeless.