Knowing Torino very well (relatives live there, and go there twice a year), and currently living in London. London offers great diversity, there are huge minorities from South America, and it is a vibrant city. Most people love to compare it to the rest of England, but it's not shite like Manchester.. Turin is a lovely city, but it's more of a town, city itself (centre) is not that big.
The weather in London is also not that bad, the rainfall here is relative, winters are never too cold compared to Germany or The Netherlands, some will argue that the food is shit, but in terms of haute cuisine the possibilities are endless.