I'm interested in getting some suggestions. Right now I'm developing an architecture which does the presentation layer using templeting. Now, my question / advice needed: Right now I'm doing XML / XSL translation. Part of the reason is I like the speed of using PHP's built in DOM framework, plus the output doesn't have to be HTML, I can output to whatever format I want. However, I'm thinking of using Smarty due to its ease of use and mostly because my architecture is for the Web. The only thing stopping me is I've heard (never fully investigated) Smarty is slow.
My questions: Do I stay w/ XML / XSL, move onto Smarty, or try another templeting engine. Please give some opinons, I would really appreciate.