We'd love feedback on Kite - a new JavaScript Templating Engine developed here at Move by @andrewterra. It has a Mustache style syntax but does include conditional sections and custom formatters (and currently 180 lines of code). In our limited testing, we're seeing much better performance than Mustache and jQuery Tmpl, but (on occasion) slightly slower performance than jQote2.
http://code.google.com/p/kite/
http://code.google.com/p/kite/wiki/TemplateDefintionLanguage
A little history - we've been evaluating templating engines for mobile HTML5 based web applications.
Thanks. All feedback is appreciated.