I have no skin in this game but I've owned a BMW. The first reply has statistics-based information that will be very helpful for the overall trends.
BMWs tend to be higher maintenance than Hondas for sure, and generally higher than Nissan. I still would not call them 'unreliable', but I would say that general maintenance is costly.
A big factor in maintenance and repair costs is the original selling price of the vehicle. Expensive cars tend to be complex and use expensive parts. The X5 would certainly be the most expensive vehicle to own at higher mileage.
That said, no vehicle is immune to wear. 200k and beyond is *possible* for any of these cars without major repairs, but some kind of powertrain component could fail, especially if the vehicle was abused or poorly maintained, and it will be expensive. There is a big myth out there about Hondas and Toyotas being some god-like vehicles that magically make it to 200k on oil and filter changes alone. Um, no. Despite any car's good reliability, this is patently untrue.