I don't think there's any reason to stay away from the 95-99 E-class Diesels. Certainly not if the alternative is a gasoline engine in the same car. From what I've read, the later Diesels are not more troublesome than their gasoline counterparts, and performance and mileage have improved considerably over older Diesels. If a later Diesel needs a new timing chain twice as often as your SDs did, so what? It's still not more frequently than a gasoline MB will need a new timing chain.

Sixto
91 300SE
81 300SD