Here are some features off the top of my head (at least that's what they claim):
- Well-integrated stack, so very little friction
- “Datomic on the front end”: Client-side time-traveling database with automatic normalization, querying via EQL (kinda like GraphQL but more idiomatic and supposedly more powerful), “co-locating” queries in the UI.
- React bindings and a Semantic UI library
- Lets you swap anything you “outgrow”
- Lots of learning material (but still lacking in some areas from a cursory look). The author seems to be very active on Slack (Clojurians #fulcro).
- Fulcro RAD[2] (currently alpha) looks like it's going to reduce friction even further.
There's probably more cool stuff I don't remember now.
The two things I'm still insecure about with Clojure are its dynamically typed nature (but I'd be glad to hear about how that isn't a problem) and that the ecosystem doesn't seem to hold your hand too much (again, I'd like to hear another point of view).