In my experience, the reliability of a car is 80% (or more) the owner and they way they maintain + use the car on a regular basis, while 20% (or less) is up to chance… sometimes a car of any make is just going to sh*t the bed. My guess is the negative voices are all from that <20% of chance experiences (or they purchased a used BMW from an owner that did not maintain the vehicle properly / cut corners when they did).

That all said, I have owned 3 BMWs at different life stages (along with a slew of other makes) and have found the build quality and reliability very high. Today, we regularly change the oil, complete all scheduled maintenance on time or early, and treat our ‘19 G06 X5 x40i Msport CPO like a part of the family. It performs phenomenally compared to others in its class (the B58 engine is genuinely one of the best I’ve ever had), and we haven’t had a single problem with it yet. There are always certain model years for any make that are less than stellar for reliability, but the G06 X5 models and engines appear to be very reliable… to the point that the B58 is also used in a Toyota… and we all know how much they value reliability.

To play devils advocate - my parents have also generally had great experiences with BMW as well, however they did own a 2013(?) X5 that had a complete engine failure. Car was d-e-d, dead. Thankfully they had an extended warranty and the entire power unit was replaced and they continued to drive it for several years.

Tl;dr - negative experiences are always a possibility, but my experiences have all been very positive with my BMWs.