If you look at reliability stats, BMW is never at the top... other than Porsche, German cars generally aren't. More focus on performance than reliability which is different than Toyota, Honda, Nissan, etc.
However, ALL cars today are pretty reliable so I wouldn't worry about it. Personally, I haven't had any reliability issues (knock on wood) in any of the 5 BMW's I have owned.
Repair bills out of warranty may be more but I can't speak to that as I've never owned a car outside of warranty
