[jsavimbi]

You sir, are correct in that. Slim also merits a looking at, but I write everything [static] in Jade first and then transfer the output to whatever, yeah, JSP's. There's a significant performance hit from using non-HTML at run time, +40% in some cases, as was Haml back a couple of years ago. Probably a good reason why RoR adopted Sass yet shied away from Haml.

[gregwebs]

The Ruby slim templates get compiled to an intermediate language (Temple). That is then compiled into an end form and everything is cached - the performance is all the same.

RoR didn't pick Haml because Haml abandons HTML. Take a look at the Hamlet language which give the best of both worlds. https://github.com/gregwebs/hamlet.js https://github.com/gregwebs/hamlet.rb