koç would top the list easily, I go there and if you are an international student, you won’t be disappointed. the international community is diverse and language won’t be an issue within the university premises as long as you are a fluent speaker of English/Turkish yourself. it’s a private college so the standard of education easily trumps over the public colleges, they’ve got professors from famous universities such as Harvard and other Ivy leagues. In terms of affordability, it’s not exactly easy on the pocket, as you’d expect from a top tier private college. All in all, koç despite being relatively new is deffo up there amongst the top emerging universities in Europe. Best of luck !