Do you have a corporate travel agent? Might check with them to see if they can get you comped status on either UA or AA.

The AA and UA benefits and perks are very different. At SFO, UA clearly wins on route network because they have a hub here. If you look at some of the AA perks, such as systemwide upgrades without a buy-up to a higher fare to play the upgrade lottery, as well as access as an EXP (One World Emerald) to first class lounges on international travel and many of us with 100% domestic upgrade rates, those may balance out the UA route network. Just about need to work out a spreadsheet and sort out what benefits have the most value to you.