Thanks for everyone's help. I did book the AA flights I was looking at, as it is cheaper than United (although Air Canada was cheapest, it would have taken longer). I won't have a lot of time for the trip as I am maxed out on vacation time, so this was the best option available for me.

The trip I mentioned from 2017 to Shanghai was on United's dreamliner which we loved. We flew Air China from Beijing to japan and I then ended up coming home on Delta which wasn't bad. Would love to try one of the Asian airlines next time we go to japan (yes, i NEED to go back to Tokyo Disney thanks to the typhoon that kept us in China that trip).