Personally I think all US airports are zoos and most people are treated like animals and not people. The experience is unpleasant from the moment you set foot in the terminal until you exit. Depending on the time of day or year, it can be better or worse. Unfortunately, its a necessary component of travel so you have to grin and bear it.

I connect in LHR quite a bit, and I know there is always a lot of bad mouthing of that airport, but I kind of like it. I havent found the transfers to be difficult at all, and the only real bad time is early morning. I was also in BRU and CDG in the last week and found them much more difficult.

The airports in PEK and PVG are really big but very clean and spacious. In PEK we had a driver and guide that were able to meet us at the gate and escort us to a hidden driveway where we bypassed most of usual activity.

HKG is also civilized.