Seeking HMO experiences (please Not Kaiser), and is an HMO viable if need access to specialists and second opinions?

I’m looking for people’s experiences with affordable HMOs, not including Kaiser, from the State. I’ve had PERS Platinum PPO (currently insured by Blue Shield) but it’s too expensive. I’d like to change to an HMO in open season, but have a rare disease and need access to specialists and occasionally second opinions (outside of a particular medical group) so not sure if an HMO is viable. I’m looking for high quality, good pricing for myself and potentially to add my spouse. Ideally: I’d like a user friendly plan and some flexibility to see different providers. - Is this impossible with an HMO? Which do you like/hate? (am in Bay Area if that matters)