Why?

While Nxweb looks very promising, my first question would be 'Why should I use it over eg Nginx?' It would be helpful to have some direct comparison to other servers on the landing page.

EDIT: Ok, there is a link to some odd benchmarks and it includes performance comparisons to Nginx and others which are not understandable (Nginx 141 req/s and Nxweb 200 / 121 req/s while it's not clear when 200 and when 121); moreover they compare it to Mongoose which is an ORM/ODM

Mongoose is a web server. See https://github.com/cesanta/mongoose. It's obviously not https://github.com/Automattic/mongoose.