I used mobx-state-tree once with great success to implement efficient time travelling in an after effects like editor (to implement cmd+z/cmd+y). In the app, the state was updated multiple times per second and it still performed amazingly. I migrated this from mobx to mobx-state-tree and as both libraries work together seamlessly, the migration was super straight forward.

Yeah MobX State Tree does really bring Mobx to the next level. Have been using it for years and it's amazing to use.