This is just my humble opinion, but when I saw the new SL for the first time, I burst into tears. It simply looked like something Hyundai would make, so artificial, emotionless and empty, by this, I don't mean "ugly" but just lacking human essence, something that a machine could design through aerodynamics. I don't know why this was the case with the SL, maybe because the previous one was so gorgeous. In the last decade, there have no doubt been models at which I have stared in awe, and some where I had been upset, but the SL was the first time I actually cried. Btw, this is very subjective and only my personal opinion, nothing more.
Like other members have said, nothing has been very "ugly," but just lacking a very specific "Mercedes-like" quality of design.