That ClojureScript is the (mostly experimental & now obsolete) work done by Chris Houser quite some time back. These two are not the same thing.
Thank both you and lukev for pointing it out.
Edit: Now they are both on the list. Gotta love Github's wiki.
That ClojureScript is actually a different project, and is a much less complete implementation. IIRC, it's not a true compiler like the new ClojureScript, but just uses macros to transform forms to Javascript. This announcement probably makes that one obsolete.
Yes, but the folks that created this one have a high reputation, and this version goes to a far extent to maintain strong performance.