I worked through the React tutorial yesterday in JS(X), and did it today in Om. I would definitely recommend doing it in that order.
I've tried to stay really close in concept to the original tutorial, but made the following substitutions to be as idiomatic as possible:
The original react tutorial repo includes a nodejs server; therefore, this one has a Clojure one. run
lein ring server to fire it up.
For getting the latest version of CLJS and Om, follow swannodette's instructions here.
lein cljsbuild once dev
lein ring server