e34 well maintained is cheap to run.
e39 well maintained is starting to see all the problems that cost half as much to fix on an e34. And are harder to resolve. However the condition is often better. As usual; depends on the candidate- with an old Bimmer, that is very much the Art of the right choice, as it is seldom the one w all the cool gear as they tend to be more an exiting hoon's ride.