Owned GL320 for 2 years. Nothing but problems.
Very cheaply built, cheap and nasty components and plastic, e.g. some sort of plastic covering film started piling off the steering wheel controls.
Fake wood trimmings, face leather, etc.
Later on I
discovered that it has common base and components with Jeep.
Mercedes Customer Service is famously the worst (watch the Top Gear) and in deed it is!