I used to drive (then) old Mercedes most of my life. I like convertibles but during those times I needed at least a mid-size sedan to pull horse trailers. I really recommend them, and my father still drives them. At the time BMW had too low quality electronics and I lived in an area with too high humidity, not a good combination.
These days my rule of thumb is that for small sedans the 3-series is better than the C-class. With new-ish mid-size I would probably prefer the base E-class over the base 5-series.