I’ve been in pretty much every big airport in North America and I’ve frequently cited Logan as the worst airport I’ve ever been in, and I’ll stick with that.
Lots of other airports have bad things about them - Kansas City’s gate-based security, Denver’s being closer to Baltimore than it is to Denver, Sky Harbor’s terribly confusing traffic (Phoenix is in general a terrible city to get around in.) Toronto has the slowest baggage return humanly possibly without actually handing the process over to professional thieves; BWI has nothing to eat or buy; Dulles has those giant buses thing (which they are working to get rid of but the project is over time and over budget, surprise surprise.) LAX is horribly inconvenient, San Francisco’s rental car counters are actually located in the State of Oregon, O’Hare and Atlanta are just too goddamned big, and Minneapolis St. Paul is a topological miracle wherein no matter what airline you flew or what mode of ground transportation you plan to use you will always have to walk the entire length of the airport to get there. I can think of something wrong with every (major city) airport I’ve ever been in, except Tampa. That’s a really nice airport. Vancouver’s not bad, either.
But only Logan is terrible in every conceivable way. Getting to and from the airport is an exercise in frustration and insanity, the airport is dank, dark and ugly, luggage return is slow, there’s nothing good to eat and no good stores, there’s nowhere good to sit and even the first class lounges are substandard. Flight delays seem to be almost as frequent an occurrence as they are at JFK and O’Hare, which is saying a lot. I’m sure there are worse airports in the Third World, but that’s not a fair comparison. It’s disgraceful for a modern, wealthy city to have an airport that terrible.
Overall I’d say the only majhor city airport that compares to it for general awfulness is JFK. And I’d still give Logan the nod.