Obviously, it hinges on one's interests. Some large cities has things that are of interest to me, and others of course. I've had good times in NYC and LA and SF. I had a pretty good time recently in Paris, better than in some of my previous visits. Boston was pretty neat, I thought. We're headed to Vancouver next month, and I'd like to visit Montreal. Copenhagen is up there in my view as places to visit. My first two visits to Honolulu were a bit down, but our last trip there turned out great, it depends on what you see and your own interests obviously. My guess is another visit to NO might be a lot better than my first two, but I'm turned off on that place.
Havana was much dumpier than I expected and Rio was as well, though Rio obviously had some nice areas, and some incredible slums.