There isn't one - UA does not upgrade elites from their own Mileage Plus program without a supporting instrument, and they do not upgrade *A elites nor give them access to Economy Plus seating. This isn't much different than how US treats UA passengers - no upgrades, no reserving exit rows, etc. Not to say that occasionally UA elites don't get upgrades on US and vice versa but it isn't common nor is it standard protocol.
All you get are the *S or *G benefits: priority boarding, waitlisting, check-in, international lounge access for *G, and I think that's about it. You will get your 25% silver mileage bonus and 500 mile minimum flying UA as a US *S, so that's something.
Last edited by ArizonaGuy; Sep 3, 2009 at 8:43 pm