> If you ask immigrants who've lived in the U.S. ~10 years or so about the pros/cons of it, though, you get much more mixed answers. Some are still uniformly positive about how much better the U.S. is than where they came from, but many aren't.

Then why are they still here?

When someone says that things are better somewhere else, I always ask why they're not at that somewhere else. Almost all the time, it turns out that whatever it is that they're complaining about is less important to them than something that they get where they currently are. Often they're embarrassed by what that says about their priorities.