Modern Car? It was basically designed in about 1975. I would say that they are incredibly reliable. They are now in all reality atleast 25 years old if you have the last one ever made. But by your list of cars closer to 35 years old.
They are setup for very different driving characteristics than most U.S. drivers like. European shift curves are very different. Even in todays current production cars. If you are having problems with reliability the valve body is the only thing that can be inconsistent for shift points. Governors fail but normally do not stick. Also the detent switch on the floor is highly problematic and can keep you out of passing gear and also always have you in passing gear. A fresh rebuild and a new detent switch and properly adjusted bowden cable and they are rock solid for about 100-150k or more.