Premium cars tend to be less reliable, but it really depends on the car. Certain models are reliable, certain brands are more reliable, and if we're speaking in broad strokes certain countries make more dependable vehicles. If you want something that will just work, buy Japanese.

I had an old Toyota that I just drove and drove and would not die. Multiple cross country trips and I never ever serviced it, except changing the oil every ~50k miles. The thing just kept on going.

I just bought a brand new BMW and I had to take it back to the dealer to fix something that broke after 5k miles.