The thing I will say about AE is that they do have a history of long upgrade times but with the amount of people they are hiring I would have to believe this will have to go down.

Also a lot of times the airlines with highest upgrade times are usually the airilnes people want to fly for, take for example horizon they have high upgrade times but that is because it is one of the few regionals people want to make careers at, and it is the highest paid regional.

you need to look at the whole company not just upgrade times

plus there are very few majors hiring so you get a quick upgrade and then you have no where to go. so look at the whole picture not just upgrade time