Programs: NZ Gold, BA Silver, BD Silver, QF Bronze, AF Ivory, FlyBe, ANA
Quite simply, minimise your time at SFO. The airport itself is fine, but the lounges are not good enough to come early for. The food in the BR lounge is better than UA, but then the UA one is completely woeful.
BR lounge gets like a zoo the two times I used it in the past year, simply not enough seating for all those using it at the time. UA RCC international is very large, so it should be easy to get a seat, but expect only to get a drink, nuts and little else if you're partial to eating before a flight.
Yes SFO lounges are disappointing for a major airport. But better than nothing of course. I used the international UA RCC before flying SFO-AKL recently and had no problem getting a seat at that time of day, though I agree it's a pretty woeful lounge. The seats looked tired and old and food/drink offerings were limited - there's coffee and tea, juice dispensers with a few different Minute Maid flavours, nut mix dispensers, packaged cheese and crackers, packaged carrots and ranch dipping sauce. Note that there's no self-pour booze, but a bar with bartenders instead.