the W201 was the first of the benzes to have the 5-link rear suspension, so you can imagine that some refinements could have been incorporated into the one fitted on the W124.

the W124 has a longer wheelbase, and along with its higher mass, results in a better ride.

the W124 has a low-liftover trunk, which makes it easier to load large objects into; of course its trunk is also larger that that of the W201.

i believe that the W124 is more refined in terms of isolation from noise, vibration and harshness.

the larger size of the W124 not only means more room for the passengers and cargo, but more safety because of the larger crush zones.

the W124 can be had with the more powerful 3.0li M103, and 2.8li & 3.2li M104 engines.

the W201 has a smaller frontal area, but I don't know if the two have the same drag coefficient.