I have test driven 2 CLA's and I have seen 5 different ones in the showroom.
It is definitely not small, but it might not be as big as you think from looking at the outside.
If you compare it to a Audi A3 there is only marginally more room in a CLA.
I consider it to be comfortably snug.
Materials and finish fit the overall look of the interior, sporty and Mercedes class. Quite good for a Budget coupe, almost up to Audi territory

No rattles during test driving the two CLA's for several hours... I would have never ordered one if it did!
Paint quality: I am asking myself if it's just me or are car manufacturers cutting corners here and there. I haver seen several brand new cars of different models, and it all looks a little bumpy.. like orange skins (if you know what I mean??) In the old days you could tell if a car had bin resprayed if the glare wasn't a 100% smooth on some panels of the car. Now it looks the same on brand new ones!