On aesthetics alone, the Toni/Katrin cover was in keeping with the Vogue Italia spirit of using new faces and had beauty about it. I'm biased towards it, memory-wise, because I looked at the issue again today, and was admiring the matt tones.
The black issue would win my vote on principle, but not on looks. Too heavy a design with that black frame, I don't need the theme of 'black' visually overemphasised to that degree.