I am aware of PBR and I find it quite convincing. Regarding QBism it's not clear to me what's the point. There is the "information processing" aspect. You have

I am aware of PBR and I find it quite convincing. Regarding QBism it's not clear to me what's the point. There is the "information processing" aspect. You have a model of physical system based on the available information (in the form of probabilities over a space of states). If you acquire more information (without changing the state of system!) you can refine your description. That's "Bayesian updating" part. If you change the system, you also get a new description. But that is not merely an update of your beliefs about the unchanged state of the system based on new information, and Fuchs distinguishes this "readjustment" from the Bayesian conditionalization. I don't think the mechanism discussed in the previous paragraph is controversial. In standard QM you can also have imperfect information about a quantum state. Then you do not have a wave function at all. You may have a density matrix, which can be used to compute the probabilities of potential measurements, but you don't know what is the underlying state. And the underlying state exists only if you have a proper mixture, but if you're looking at a subsystem of a larger system in a non-separable state you have an improper mixture and even if you had perfect information about the composite system there is no wave function describing the subsystem. Then there is the "quantum state is not a description of physical reality" aspect [1]. But you can have the Bayesian description of our knowledge of quantum states without breaking the link between quantum states and physical states (and I'd say that according to PBR if you have perfect knowledge of the quantum state, i.e. you have a wave function, then it does correspond to a physical state). We could also apply the same treatment to Classical Mechanics: The states of the system correspond to points in a phase space. The "information processing" aspect looks reasonable: we can describe our knowledge about the state as a probability distribution over the phase space, refining our knowledge means getting a more concentrated distribution as we incorporate additional information. We can also interact with the system, so we get a new description that is not simply a refinement of the previous distribution but incorporates the physical change effected. In the case when we have perfect knowledge (our description is a point in the phase space) we know how this point will evolve and no information can be gained at all. But we still can perturb the system to a different point in the phase space (this is what Fuchs would call a "readjustment"). The "state is not description of physical reality" aspect do not look so reasonable. We can say that states do not exist. Those points in phase space do not describe physical reality, they describe only the observer. There is not such a thing as a right and true state of the system, if such is thought of as defined by criteria external to the agent making the assignment. States must instead be like personalist, Bayesian probabilities. We can say all that, but what is the point? I don't say that there are not issues with QM, but I don't see how QBism does solve them. Whatever the problems may be with the "quantum-states-are-physical-states" approach, the "quantum-states-are-not-physical-states/physical-states-are-something-else" approach may get rid of some of them but that's not exactly solving them and introduces new issues in defining what is the relation between "quantum states" and "physical states" (hopefully there is some, if we're doing physics). [1]: which is controversial, here QBism is closest to the “hardcore” Copenhagen view (the wave funciton is a mathematical device used to calculate in the context of an experimetal setting) than to the "standard" QM theory which is based on the state of a physical system being described by its wave function.