I've had my car for a few years now and put a good bit of miles on it. I've got 120,000 miles. I've changed the battery, tires, oil, spark plugs, all the regular maintenance and it drives great. But it's a BMW and parts are not cheap. . . it's also not cheap to have someone put them in for you. If you want a car that is Cheaper to keep going, drive a Toyota or a Honda. If you want to enjoy driving your car get a BMW. Previously I've had an Rx-8, MiniCooper Sport, Lexus SC430 and a Honda Accord.
The Ultimate Driving Machine sucks in terms of reliability. I bought my first and last BMW 3.5 years ago while it was still under their their Warranty/Maintenance plan. However, I have had leak after leak before and after the warranty expired. I think I have replaced the whole cooling system and oil system. Every day before I drive my car, I have to check the undercarriage plate to see if I got another coolant or oil leak. Plus the "engine malfunction, increased emissions" light always come on and the engine start shaking and its always caused by a different part. Do not buy unless you plan to buy several extended warranties and pray the parts are covered.
I bought mine in 2008 with 28K miles. I sold my 2003 325i to get this car. Just like the 3 series, I LOVE the way this car drives. The power, acceleration and steering are incredible. It's super smooth at high speeds - you just don't know you're speeding! After about 50K miles I was experiencing jerkiness in the transmission. Sometimes at a stop the engine would race and I'd have to shove my foot on the brake. I mentioned it several times to my dealer and finally, at 99K miles (I had the extended warranty) I asked to have a mechanic ride with me and I got a new transmission :) Cupholders suck; don't like the iDrive and interior is so-so, but I still like the car!
I had 3 cars sitting in my garage, one was a BMW 545i (2005) one is a GMC Envoy (2002) and the other is a Toyota Tacoma Truck (1996) The BMW continued to leak oil all over the garage until I finally sold it. The Envoy and the Tacoma have about 200,000 miles each and I doubt that I have even spent $500 combined on the 2 of these cars since I have owned them. The BMW has been nothing but problems with every maintenance bill being at least $1,000. Just a battery alone for the car is almost $500! The car was the best driving car I have ever owned but reliability was the worst of any of the 20 cars I have owned since I first started driving. I traded it recently for a Toyota!
I love to drive my 525i, but it would be a lot more enjoyable with some sort of stereo. CCC module went out and is $1700 to replace. Out of my budget and almost inevitable to go out in this model. This controls navigation and all the service lights so I love my car a lot less than I could have. How I wish BMW would recall their obvious faulty CCC module so this car could be the great car it was meant to be.