In fact I lived there for a few years, and loved it. I would rather live there than, say, Seoul, Tokyo, or Berlin. In fact, I made that choice once, choosing an expat assignment there over Tokyo.

Opinions are just opinions, but in my opinion (along with most of the other expats I knew who lived there), it is a world-class city in most ways that the ones you mention are. It is a vibrant city with tremendous history, culture, energy, architecture, beauty, etc. It has hosted the Summer Games and two World Cup finals. It contains historical sites and sights that few other very large cities can rival. Its restaurant scene and nightlife are up there with the best of them. It is home to great museums, including one of the top few archaeological museums in the world. It has one of the world's great city parks (Chapultepec) and one of its most interesting and beautiful major avenues (Avenida de la Reforma). Pretty much every major multinational corporation has a presence there. Almost every nation has an embassy there, and most major airlines in world fly there. It has great shopping and some incredible residential areas. It is surrounded by very tall, beautiful snow-capped volcanoes and forest-covered mountains, and there are tons of recreational opportunities within a short drive of the city. The weather is spectacular. Beautiful tropical beaches are four hours away on the expressway. One of the world's greatest and best-preserved ancient cities (Teotihuacan) is in the suburbs. You could easily spend every weekend for two years doing short day-trips or weekend trips by car and still not see & do all the interesting stuff there is to see and do nearby (believe me, I tried).

It is a third-world city, for sure, with most of the problems of big third-world cities, but it is one of the great cities of the developing world. If your definition of "great city" includes only rich, first-world cities, then so be it. I don't agree with that definition, but I understand that some may feel that way. I'm very comfortable labeling it a world-class city.