Interesting. Looks like it maps TeX directly to HTML, so it must support fewer constructs? Or what are the downsides? Being 10x faster and 10x smaller without any drawbacks seems too good to be true.
"TeX-based" is the operative term here. The syntax is somewhat different true TeX (so it would drive people who use TeX regularly crazy, like me). And I don't believe it has the same abilities.