I have 4 BMW's in my garage, was 5 last year. My 2005 530 has 306,000 and has been flawless (one fuel pump and starter..has oringal water pump...don't understand how) but still looks great. My wife X3 at 200,000 miles has been flawless only major was a AC exchange made by beur? that failed...the shop had never replaced one. My 850i was fantastic I owned for 8 years, not a daily driver. My 2005 R1100s Boxer cup bike, 12 years and 23,000 miles not one issue. My 2013 R1200gs 24,000 miles not one issue. I have many relatives and friends and neighbors that drive bimmers, they don't seem to have a problem. My sisters745 was a problem, but the 740 before was not. My moms X5 its been fantastic.
First of all I want to apologize for my fanboy coming through in that comment. But I have more to say on the subject.
BMW and Mercedes were very different companies up until the the E65 7-series. And up to that point, the only time BMW produced an all around superior car to its contemporary Mercedes was the E39 5-series, which was distinctly superior to the W210 E-class- as safe or safer, similar reliability, superior luxury, and of course, worlds better handling.
Thats not to say that prior to that point, BMW built bad cars. Certainly not- but they were much more distinctly more driver focused, less luxurious, less comfortable, less refined, and certainly less safe. They were vastly superior in road feel, handling, and "fun-to-drive". Take the E36 3-series, for example. That car's competition to the W202 C-class was at best lop-sided. The C-class was roomier, quieter, more refined, more solidly built, and unquestionably more luxurious. It would not be an exaggeration to call the interior of the E36 downscale. On the flip side of the coin, I don't think anyone ever built a superior drivers sedan.
For the generation that encompassed the the W220 and E65, it would be accurate to say both companies were lost- BMW had foregone the driver orientation that made their name, and Mercedes was still disoriented from the sucker punch that was the first and second generation Lexus LS, and the W220 S-class was frankly an embarrassment- even Mercedes themselves admits so. But where Mercedes regained their footing, dismissed Lexus as the flash in the pan their true luxury aspirations were, and hit one out of the park with the W221 S-class (and then nuked the ball park with the W222)... BMW held to the basic course for all their cars that was laid out by the E65.
BMW's current cars are neither sufficiently overall amazing to compete with Mercedes offerings, nor driver-focused enough to define their own segment- as they once did.
My experience through friends and family is that BMWs tend to be less reliable than Mercedes cars, although post-W124 offerings are not nonpareil in that aspect. However, I was talking more about building cars that either redefine the standard for the segment, or offer something sufficiently different to place them in a class unto themselves. BMW has done neither since the E39. I would go so far as to say that since the E39, Mercedes has had more competition in that area from Volkswagen (The Phaeton was the real top of the class until the W221 debuted) and Hyundai-Kia (the Equus, K900 and most recently the G90 bear watching) than from BMW.
And that is my own opinion of course. And I'm glad you have had such good experiences with your Bimmers.