Orleans is neat because it tackles orthogonal persistence and fault recovery at the same time. Lots of interesting future work remains to be done with persistence, though: wouldn't it be interesting if there were some "third way", somewhere in the middle of spectrum between (1) traditional orthogonal persistence, which serializes the entire nitty-gritty program state (stack, register file, heap, etc etc; totally implementation oriented), and (2) the Orleans or SQL-ORM approach, where the programmer manages records explicitly and, if they're lucky, gets a bit of support to give them a reactive feeling? I'm imagining some kind of domain-specific reflection on machine state, so, a bit like traditional persistence, but filtered through a domain-specific summarization function to yield a domain-relevant data structure describing the state of the actor.