London by far, best people, best hotels, best nightlife, lots of history, wonderful museums, art galleries, plenty to see and do. Never be bored in London. Every nationality, fast paced 24 hour party people, but also slows paced, slow walks in some of the best parks in the world. Takes a bit of beating!
It depends what taste you have. In Most places, people say that the best cities, are the capitals. Take an adventure and explore!!!
Do you even know what "digital marketing" IS?
I bet if you look THAT up, the answer will be obvious to you.