I used to have a 380SEL and it was a pretty good car. For my case, the interior lighting (fibre optics) start to go one after the other. Well, functionally still ok but not as nice.

The fuel pump seems to go every 9 months.

The engine eventually starts to go (for my case eas 480K Km)

Yes, it consume a bit of gas especially towards the end of its life.

To be honest, it is a fiarly cheap to maintain car.

Michael