I've read a couple of CRDT papers but never used them in anger. (Zero interest in collaborative text editing, but a lot of interests in multi-master systems involving local databases that lose internet connectivity).

Anyone have any good war stories? The general impression I get is that anything more than a state delta two-phase set is an open research problem to implement efficiently - the papers make it sound pretty straight forward but there's a whole garbage collection problem to deal with, there was another research paper dealing with just that IIRC.