Looks good, and that was a side project I was going to do. Glad I didn't.
I tell you though--it speaks well to Mercurial's UI and usability that I really don't feel like I need any graphical UI. The CLI is easy and fast.
I just can't get used to using GUI SCM clients on OSX. I tried to use ZigVersion for svn but just couldn't integrate it into my workflow -- I'm too used to using the command line for svn, git and hg.
It does look nice though.
I like it, almost as nice as GitX which I'm sure it will match it soon enough :).