I definitely prefer flying AA C and absolutely JL C or even more obviously JL F from Japan to the US over United or even ANA, but as much due to oneworld emerald lounge/etc handling as anything onboard. Vaguely wonder what AS and HA tpac are like.

OTOH, I got a one-way HND-SFO on the specific date and time I needed for 55k UA miles in economy and upgraded cleared 96 or 120h in advance of flight to business using 40 PlusPoints so I can’t complain at all.