For me, it depends on age. London is a massive city with crappy weather, but nonetheless NYC caliber. If I'm under the age of 35, the answer is London. But if I'm older, the answer is Turin. Now, I will admit I've never actually been to London but I'd expect it to be an older, rainy New York. If I'm young, Turin would become boring quickly, while London would always have something to do. If I'm older, Turin has a community feel better food, nicer ambiance, community feeling and superior outdoor activities. If I'm a city dweller, I probably prefer London but if I like to ski or bike, I think Turin.
For me? I'm 29, and a complete city dweller so I'd take London BUT if I have a job in Juventus front office And could go to most of the games, Turin. Lol.
That being said I have actually been to Turin and it was my favourite city in Italy. I went to Florence, Rome, and Milan too. Florence was obviously beautiful as well but preferred Roma to Florence. Roma is also where half my family is from. Milan was an ugly ugly city. I also saw a Roma Europa league game while there (they drew against some crap Austrian team, pretty funny. And also the stadium atmosphere was horrible, especially after seeing a game at Juventus stadium.)