We shouldn't talk about "objective best" without pinning down what that means. I can only really imagine it in a sort of Aristotelian sense - a city could be the best city because it most fully embodies the notion of what it means to be city (as opposed to a more rural or suburban area): a usually cosmopolitan agglomeration of people where the density/economies of scale/competition create an environment that allows art, culture, entertainment, public services, etc. to flourish. In that particular sense I think NYC is the clear best city in the country, no competition, with maybe Chicago being a somewhat distant runner-up. In that mode of thinking it's arguably the best city in the world, actually.

Now, that said: when I lived in the US I (mostly) preferred living in Seattle over NYC for the weather, natural beauty, and more laid-back vibe...subjectively Seattle was better for me, but I still don't have an issue with saying NYC is "objectively" a better city than Seattle.