Just for fun, I wondered if folks had their own ranking of the mainland UA hubs (so excluding NRT and GUM) that they preferred. Below is my list:

1) EWR - great Polaris lounge, appreciate the ease of use of shopping/eating at the OTG restaurants. New waiting areas next to gates have lots of power & can order food. UC in Terminal A is good but the UC situation in C needs to improve
2) SFO - favorite from an in-terminal food standpoint, spacious (if aged) UC in the rotunda. Like the arrivals lounge as well
3) LAX - best domestic UC; easy to navigate; Terminal 8 is kind of wasted space right now
4) ORD - lots of UCs, decent selection of food vendors, terminals can get a bit crowded
5) DEN - spacious but almost too much so; not a heck of a lot of spots to stop in the main terminal area; UCs are showing age
6) IAH - a bit spread out; TBH is the UA hub I transit the least so have very little in terms of strong opinions
7) IAD - still in a temporary terminal 30 years later...need I say more?