Aside from upgrades, you had mentioned you are 7 MM with AA. UA counts miles differently for lifetime purposes.

AA used to count credit card spend as accumulation of MM. Upon moving to loyalty points, credit card spends no longer count toward MM. It's now all about BIS, butt-in-seat, similar to UA. AA, however, still counts partner flights. UA you have to earn it one mile at a time for lifetime miles, no bonus, no credit card, no partner earning.