From Cardesignnews.com

"Mercedes-Benz CLS

At first sight the CLS might appear to be a solution to a problem that isn't there; it offers no more, and in some ways a lot less, than the cheaper E-class upon whose platform it is based.

The car is a large four door, coupe style sedan with an imposing new variation on the Mercedes Benz family face that has the brand's coupe specific grille flanked by L-shaped headlamps. But its character is defined by a sweeping side feature line that runs off at a tangent from the front wheel arch in a single strong arc to the rear lamps, echoed above by the base of the shallow DLO. This sweeping profile is further reinforced by the sweep of the upper DLO and tapering tail of the car.

The CLS makes sense as it fills a niche between the established Mercedes Benz sedan and coupes. And the specific problem that it solves is for the wealthy empty nester who still wants the practicality and image of a large Mercedes sedan, but doesn't want the family/business man image of the E-class." SL

I think this is a very valid point, but doesn't give the CLS any credibility as a "four door coupe", just tells it like it is.