I've owned several Benzes (a fan of W126 & W124 & W123 cars) and while I've not (yet) owned a CLA, I've seen them & sat in them a number of times. I have to say that when properly equipped, the interiors are every bit as nice and as comfy as any other Benz. Sure, you have the screen which is not integrated into the dash, but that is not a bad thing. You can get wood on the panels and the seats can be fitted with the ideal MB-Tex (quite a solid reputation for comfort and longevity and ease of care) or leather. I am 6'6" tall and can fit in the front with lots of legroom and headroom. While the back seat is not ideal, I can still fit in it without discomfort. I am not sure if it would be ideal for me to ride in the back for a long period, but around town, it's not that bad. Being retired, there is not that much of a need for us to haul people in the back seat anymore.
And, I like the style. Very fresh, very aero and allows for it to be unique and not (yet) appear as a Honda or other Asian car. It is full of standard features and can be optioned to the hilt if you so desire. (For me, the simpler the better.)
Finally, being a FWD car, it is a great way to provide a less expensive drivetrain, use a powerful 4-cylinder motor with great economy and low emissions, and have it feel more normal to most people who have never driven a RWD car in their lives. MB will be building a lot of these cars over the upcoming years and they will not suffer from being like the 914 Porsche was to the 911. I know the bugs will be fixed as they always are at MB, and the CLA will (continue to) be a proud member of a exemplary line of automobiles.