For me the E was the perfect car. Large saloon, big boot, super comfy drive, fast in E350cdi form, takes 3 kids with no issues.
However, I loved and still like the original W212 shape. Bought in 2010. Still driving it. Still enjoying driving it. Still love the shape.
You have to love the look of your car. It also has to look after your needs. 1 kid soon becomes 2. Kids grow up, have birthday parties, have friends over etc etc.
I think CLS looks great. If it's a car for a few years only then it will tick your boxes.
If your looking for a long term motor then perhaps think again and look for a car that ticks all boxes. Maybe non merc as well.
Whatever you do, but a car that turns you on.