I have been 1P for 3 years now and Plat up until February this year although I get it back this weekend.

Being based in NYC and also totally on my own dime I have moved completely to AA and am giving up 1P

Here is how I see the comparison.

UA Plusses.
Channel 9.
E+
Better options to Pacific.
PS

AA Plusses.
Better flight selection from NYC.
Better able to upgrade.
Better domestic MR options with use of alaska at times.
Better chance to hit lifetime levels because ALL miles count.
Cheaper Awards to South America.

Both airlines give 100% RDM and EQM on all domestic travel. AA give 50% of EQP only on deep discount.

Given the SFO outlook of this question I would still choose AA due to AS possibilites on the west coast.
AA exit row makes up for E+ in most cases. I find you can almost always upgrade on AA when you want.

The comment about AA "O" fares not earning miles does NOT apply to domestic travel. ALL AA domestic travel earns miles.