I live in Hawaii, but used to live in the Bay Area. Here are my thoughts to help a Bay Area traveler decide:
Without question, HA offers the most consistent pleasant experience.
In terms of personnel, HA is the best between the Bay Area/West Coast and Hawaii. They are not perfect and sometimes you will have the occasional rude/lazy/apathetic agent or FA, but later on during your same flight/trip you'll meet someone who will just blow you away and make up for the other person. AS comes a close second (judging pre-VX merger) and UA is the worst.
In terms of food, in first HA is better than AS, but not as good as UA/AA and honestly, it's probably the lack of ice cream sundaes that does it for me. In coach, HA has really downgraded their free food and I would probably pass on what they offer now. I like AS's BOB program better than HA's free food and UA's BOB so win for AS.
In terms of aircraft, the A330 in first is the best product from the Bay Area and the A321neos in first is the same as a AS/UA 737. So in first a win for HA. In coach, I still give a slight edge to HA if you're flying the A330, but essentially a tie.
In terms of FFP, HAMiles is by far the worst program between UA/AS/HA. I was AS and UA Gold over the past couple years and give a slight edge to AS here.
In terms of lounges, HA and AS have none in the Bay Area so UA wins.
In terms of schedule, HA flies to all 3 Bay Area airports w/ flights to HNL and OGG and an upcoming OAK-LIH. All have the same schedules--AM departure, PM return. UA wins hands down w/ frequency and variety of departure times (AM, afternoon, redeye).
Seeing that you're UA Gold, I'd probably stick w/ UA and try for 1K. And w/ WN entering the market, you might want to stick w/ them and bring your companion along.
As a disclaimer, my personal bias remains HA then AS then DL. I reluctantly fly UA and AA only when they are at least a thousand dollars cheaper in first or my schedule is just not flexible.