Going off the above, the addition of VIE makes UA the clear winner, hands-down.

HOWEVER: your frequency of travel to VIE is important here. I say that because it just so happens that AA also has very good service to both NYC and LAX from ORD with hubs at both as well (though of course theirs is more heavily split between LGA and JFK than UA is between EWR and LGA). So, if VIE is just a couple times a year, you MAY find AA to be equal/better for the NYC and LAX stuff according to your personal needs and travel patterns (times, equipment, etc.).

Not to diminish to obvious advantage of the UA/*A angle here, just playing a Devil's Advocate role insofar as if VIE is just once or twice a year, you might find AA better overall if the NYC and LAX options better suit you and you suffer a bit via LHR to get to VIE.

But yes if VIE is at all a frequent destination for you, you will become very familiar with the OS onboard chef and all that goodness.