I don't have a very high opinion of United, because of bad experiences with their Shuttle by United operation. Having a hub in SFO itself it a bad idea, as it has the highest number of weather-related delays in the country. Then when there are problems in SFO, the airline essentially grinds to a hault, and the passengers start piling up in the terminals. Shuttle's Terminal 8 at LAX is small and has extrememly limited seating, and can easily overcroud when this becomes a problem - though I've heard something about a rennovation that would improve it. Still won't help improve reliability at SFO, though.
It's hard to blame United for SFO's weather problems (aside from choosing SFO as a hub), but the handling of the situation was not especially good. The time I was stuck in Terminal 8, the terminal staff was ok but what exactly was happening was unclear, and then they were a bit terse when they needed people to clear a space for passengers when planes started coming in. It was partially a problem of where to put people, but then we can again trace the problem to United for not providing sufficient space.
I've also found the flight attendants to be indifferent, at best. Again, Shuttle may be different from the mainline, but it reflects badly on the company. You want United basing? Head over to http://www.untied.com/
and see why Rising may be little more than a marketing slogan. Don't worry, indifference isn't just a United phenomenon, I've seen the same attitude with American/American Eagle's ground staff (the Eagle flight attendants were ok).
Also note that United is eliminating their Honolulu crew base. Employees have to fly, on their own time, to another airport (SFO?) to work if they want to continue to live in Hawaii. Before that agreement was reached the situation was starting to get ugly in Honolulu.
My suggestion for those flying Chicago to Honolulu, is to fly your airline of choice to Los Angeles (Delta would be mine), then board a Hawaiian Airlines flight. And since we're spouting corporate marketing slogans, remember that Hawaii is Everywhere Hawaiian Flies.