Due mostly to my dissatisfaction with the new SWU rules, I've flown about three times as much on American so far this year as I have on United. My only miles on UA metal this year were in F from FRA-IAD and then on a babyjet from IAD to LGA, so bear what I'm about to say with a grain of salt:

United's not so bad; or at least, not much worse than the competition. Comparing recent flights in F from ORD to LHR on AA versus FRA to IAD on UA, I'd say that my flight on United was superior in almost every respect.

Having said that, I'm still unhappy about the new SWU rules, so I'm still more interested in earning EXP this year than 1K and will probably continue to fly AA more than UA.