I've been really impressed with the old W124 chassis models, since it was back when "spare no expense" motto was used towards engineering the best.
If you can find one that has been well maintained and protected from the elements, you'll wont be disappointed. Also imagine the money you will save and can put towards more modern upgrade versus a newer one. Since, most the newer models they had to cut back on quality parts to save money to compete with the Japanese imports.