A display at the Gosford Car museum offered an interesting comparison between the Ponton and Finnie 220S models with two parked next to each other in the same colour. The W111 finnie set a design trend through the 60s and early 70s for Mercedes.
Obviously the major differences are at the front and the back with the tail fins, updated lights from the 300SL roadster etc, but there are numerous subtle changes that show the evolution between these two models. The Mercedes grille started its transition from tall and narrow to wide and flat over 50 years with this model, and the W111 shared the trend with many late 50s designs with a much larger glass area and ‘airy’ cabin.
The lower spec W110 is actually more visually similar to the Ponton, but I personally find it a rather awkward transitional design compared to the W111.