Boston has equally horrible weather, and IMO is not more beautiful than Chicago.
So many SF people are pretty annoying, and it costs absurd amounts of money to live in absolute shitboxes.
SD obviously has the incredible location, but it isn't nearly the cultural center* that Chicago is. (*This matters more to me than weather or "beauty").
Chicago is every bit the cultural center SF and Boston are, but with lower prices and nice midwesterners that KK alluded to. And Chicago is a "generic megacity"? What other cities would fall under this label?
what the people are like isn't a consideration for me. you can't include cost of living. almost by definition (probably only excepting cities in third world countries for first world buyers), great cities are going to be really expensive because more people want to live there than exists space for people to live.
chicago is a nice city, and i agree with you that it has some beautiful architecture. by generic megacity, i mean it's about the same in terms of cultural offerings, urban living options, etc. as most other cities of a similar size. i mean it's nicer than phoenix or houston or whatever, but it doesn't compare favorably to the more historic cities on the coasts or in other countries. and the weather really does suck.
i do love the easy & cheap public transport from ord to the city center. that's something every city should have, and an amazing number do not.