Well I'm booked for next Sept on Avios. Had been thinking about a West Coast trip, exploring Oregon and N Cal so this is better located than SFO. Neither of us are Gold any more so hoping the new Gatwick S lounge is at least as good as T5 Galleries Club. But OAK is particularly well located for what we want to do, although I wouldn't think twice about it for a trip to SF city.
OAK - Montgomery St BART is 37 minutes, SFO - Montgomery St BART is 30. Given OAK is a quieter airport, maybe it'll be quicker through there and that would even out...