Upwardly mobile: are you living in the wrong city?

I'm not a big fan of city-rankings. Part of the problem is the the most simple rankings usually only consider one or two aspects of cities, which don't capture the complex trade-off faced by households and firms. In contrast, once you consider a lot of factors, you need to somehow collapse these down to get one index. Then the problem is what weight should you give to each of the factors?