Rio de Janeiro
I know this question is very specific, but bear with me: Considering using United for a trip, from Sao Paulo to Lax, which is better: Going thru Houston or Chicago O'hare to make the connection? I don't know these airports so i don't have a parameter. The main idea is to have a better customs experience before connecting from these airports to LAX. Flying United or AA.
Suckage about the same at both, IMO, although I have only entered through International in IAH. You ride out to the International and back by shuttle at O'Hare. The same is true in IAH. It really depends on how much hoofing you have to do to get to the train.
I would probably choose IAH myself, as you have a bit less flying, but it is International. Customs sucks at both unless you can get Global Entry.