I tried to use it a while back but found it a bit bureaucratic for a startup. Felt better-placed for large orgs with distinct product management teams.
But going through the process of creating an experience map was so interesting, it helped us realize how little we knew about some parts of the user experience. And the idea of regularly engaging with users is very appealing to shorten the feedback cycle. Sometimes there are little things you could do for cheap that add a lot of value, I am hoping this will help find them more efficiently.