(Sorry if some people find that this is a copy of my HN comment. It is, hope that’s okay.)
The about page gives me no idea of what it is, especially as someone who knows TeX quite well. It starts with the single mistake all of those pages do: “It’s like A, but with B!” On top of that, B is already in A. Typesetting with scripting? LuaTex (actually quite easy, if you know the typesetting surroundings). More layout control? ConTeXt.
The biggest hurdle in all those systems is understanding what typesetting actually is (in contrast to content editing or especially programming). It comes with a completely different vocabulary. What’s a strut? What’s a quad? What are the standard elements of typography and page layout. How are fonts measured?
Finally: how does the system manage forward compatibility (can I still compile my document from 5 years ago?) - scripting and modularity are features that have to be evaluated under all those regards.
Also, I am very surprised that code examples in the reference documentation look horrible. Isn’t that what the system is there for?
That said: I love that there is competition in that space and they seem to know their stuff. TeX is great and will be around for a few decades, but that doesn’t mean there can’t be others.
 http://en.wikipedia.org/wiki/Strut_%28typesetting%29  http://en.wikipedia.org/wiki/Quad_%28typography%29