I've driven it.
As a C-class owner, I believe I can be a bit more objective than a current E-class owner on this issue.
I've seen and driven the New E-class, E250CDI, E350CDI, E350CGI and E500 and the E-coupe as well.
To be honest the initial photos had me scared on the looks, like the CLS did when it was first being launched. However, after seeing the new E-class in the flesh, then driving it, color me impressed. The jump in design and quality, of the new E-class, feels as big as the jump from the 163 ML to the 164 ML.
The new E-class looks very nice in person, modern but still with a conservative, older person, touch. It looks best, to me, with the AMG sports pack, but that is a personal choice. Actually, Palladium Silver with the AMG kit was the one I liked best. It feels very solid to drive and very comfortable, yet more sporty than the old model. Though I think the latter is due to the new more direct steering wheel and suspension settings. NVH levels are the lowest yet.
With the thermotronic climate control there is a diffuse setting where it send the air around you instead of directly to your face and this is the first time such a setting has worked so well. Night vision is also a welcome new option, amongst many others.
Overall, a very worthy successor!