Personally, I think Rio's font fits well for Rio - it has the wavy look of a seaside city and the colours are very Brazilian, giving off feelings of the youthfulness and vitality of the city. It would look odd in London, because it is a historical, northern European capital city but nevertheless its colours and font match the youthfulness and vitality of that city too. I think both concepts, therefore, perfectly match the cities they are meant for, yet are totally different in concept. I mean, if you put either of those designs anywhere else (Paris, L.A., Tokyo, for example), they would not fit either
It goes beyond matters of taste, and enters into the sphere of appropriateness. And both do their cities well.