The primary goal of Outlet is to develop games, so it will be fast and portable.
ClojureScript has different goals, and is primarily meant as an extension of Clojure.
* sophisticated debugging, introspection layer (in browser would be possible)
* fast, portable
You should be able to develop games as easily in ClojureScript as you would in Outlet.
That said, Outlet is very cool!
I'm really interested to watch ClojureScript develop, and it already has an amazing community (and surprising awareness among devs). I probably need to hack on the source before I make assumptions about it.
I'm enjoying the freedom of building a new language though, and things like compiling to Lua and debugging aren't as nearly overwhelming because I'm doing it from the ground up. Who knows though, if I get comfortable with ClojureScript I could eventually just contribute to that.