At least two of the older Mercedes with power windows I have driven had windows on the fritz.

German cars, whether it be Audi, BMW, Mercedes, or Volkswagen - love to eat window regulators, switches, or what have you.

Consider this: Whenever I see a W123 240D that I'm looking at has power windows/sunroof, I consider it a strike, not a bonus. No sunroof, no power windows - that's the way to go. I'd be fine with manual door locks too...