My view of larger cities is that they have nice areas and really bad areas. There often isn't much in between.
Boston was fairly nice, didn't like the weather. San Francisco is fine with me, the weather is upside down often. San Diego seemed nice enough what I saw of it. DC is wonderful in places and awful in others, a lot of gentrification happening there. Chicago is another example of that without the gentrification.
Philly, Miami, Dallas, Houston, all have nice spots and bad spots.