More generally I get worried about my ActiveRecord objects getting too bulky and business logic getting all wound up in post-transition callbacks and such. But that's something that can be managed with service objects and being disciplined about triggering state changes.
I used this for a huge project with a lot of states. Separated my workflow out into individual files for each class so they could just be included at the top. Then for each transition method, I created a service object (Interactor gem[1]) to handle all of my complicated transition logic, so the object-level transition methods would just check for a success or failure and perform the transition appropriately. Really love how it turned out.
More generally I get worried about my ActiveRecord objects getting too bulky and business logic getting all wound up in post-transition callbacks and such. But that's something that can be managed with service objects and being disciplined about triggering state changes.