Welcome AVeliki,
I have had a 2011 E350 Diesel and currently run a 2015 E400. My wife runs a 2015 C220.
Nothing wrong with the E350 in fact it was great car, very smooth. But I wanted a change for various reasons.
I much prefer the E400 partly as it is newer with higher spec and partly because it is petrol (3.5). It is more powerful when I want it to be. I mainly run it in ECO mode but when you want to make progress SPORT really does make a difference. I do a low mileage.
Be careful if you look at this model as in the UK most dealers/sellers do not realise there are 2 different engine sizes. I had to look at V5 to make sure.
As far as top down motoring is concerned I use mine, top down, in all seasons when dry.
Funnily, hot summers (more often these days in UK) can be the worst time for my comfort as I burn easily.
The air scarf, heated seats, windows and rear wind deflector make the cabin a cosy and warm place.
As far as problems are concerned I have had the dreaded NOx problems (about 2.5 years ago), but, MB fixed FOC once the second dealer realised I had 4 sensors.
Personally I would plump for either the 350 or 400.
Regards
David