So I did a quick work trip from ORD to MSY this week. Flew down on a rare AA domestic one way FC ticket due to meeting schedules. Flew back this morning on my normal UA flight Domestic First.

My thoughts:

AA Flight down:
H/K Admirals Club was solid. Bartenders were not very efficient. Standard food selection, salad stuff, snacks, etc.
No food offered on plane other than a nice selection of assorted snacks.
Wide open PDB service which was really nice
Flight attendants were awesome
Aircraft was a 737-800, seat was nice, cabin was nice.
Overall good experience although food would have been nice on a 6:30 PM flight.

UA Return Flight
United Club: did not visit because it is in C concourse and for some reason we departed out of B concourse
Hot breakfast on plane. It was ok, ate the eggs and the bread and fruit.
PDB was water or OJ only which was fine on an early AM flight
AC was also 737-800 with seatback video. Cabin was dated
Flight attendants were solid

Both flights were on time.

Overall, factoring in the plusses and minuses I would call it a tie or a slight lean to AA.