The 116 diesels were the first of the turbodiesels brought to the US by MB. The engine is very similar to that found in the '82 to '85 300D's and the 126 300SD's.
There is a bit of a following for these cars. I think they are really neat cars. They offer good fuel economy, body and chassis construction worthy of a three pointed star and durability. The name plate should say 300SD.
As with ANY used car, condition is everything. Just because it is a particular model, does not mean you should buy it. If you are not experienced in evaluating used cars, you should find an experienced, and honest MB specialist and pay him to inspect and evaluate the car.