When comparing Mustache.js vs Closure Templates, the Slant community recommends Mustache.js for most people. In the question“What are the best JavaScript templating engines?” Mustache.js is ranked 4th while Closure Templates is ranked 19th. The most important reason people chose Mustache.js is:
Mustache provides you with a clean and easy to understand syntax. Having a syntax that is readable is always a huge plus, since this means easier maintenance and code readability in the future.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Clean syntax
Mustache provides you with a clean and easy to understand syntax. Having a syntax that is readable is always a huge plus, since this means easier maintenance and code readability in the future.
Pro Available in lots of languages
Available in a wide variety of languages including Ruby, JavaScript, Python, C++, Scala, Go, Julia, Swift and more. See the full list here.

Pro Lightweight
Mustache is easy to deliver. If you need more features down the road, you can switch to handlebars, which is a superset of Mustache.
Pro Logic-less
By design logic-less templates force you to separate concerns thus helping you avoid future problems with refactoring. It also allow templates to be used with multiple programming languages without changes.
Pro Server side support
Mustache.js has multi-language server side support, which essentially means you can use mustache based templates on languages other than javascript. (like if your server-side was built on Java you could still use Mustache.js)
Pro Popular
This would mean that you'll have a large community to help you out if you run into any problems.
Pro Can be compiled
Mustache templates can be compiled to JS files, so that they can be directly loaded.
Pro Language independent
The same template written in Closure would work both on Java as well as javascript.
Pro Well Tested and used by Gmail and Google Docs
Closure Templates being a project created by Google, is extensively used in some of the world's most famous and largest web apps which include Gmail and Google Docs. What this means for you is that you'll be using a Template engine that has not only been intensively tested but also that you'll be in good company, with lots of technical support.
Pro Secure
Closure has been designed keeping most security risks in mind. Templates created using Closure are auto-escaped automatically. Hence you won't have to worry about any XSS attacks.
Pro High Performance
Closure templates do not tend to slow down your site's performance or increase your page load time. They're compiled to extremely efficient JS code so that your page renders extremely fast, whether the templating is done on the client end or the server end.
Cons
Con Basic tasks are difficult
Mustache js's attempts at making some things simple makes them so easy that they're almost difficult. That is the case with some basic tasks like figuring out how to apply css to shade odd/even rows on your template based content.

Con Bested by Handlebars in many ways
Handlebars being an extension of Mustache bests it in both speed and power. It adds additional features to Mustache which make writing templates easier and faster.
Benchmarks have also shown that Precompiled Handlebars renders in about half the time of Mustache and the rewritten Handlebars (current version) is 5 to 7 times faster than Mustache.
Con Hard to find what you need in documentation
Docs are pretty, but hard to find exactly what you need. Although language has nice macros, you're going to hate them when they fail and you search for info for half an hour.
Con Strange errors from compiler
You won't get used to them even after a while.
Con Not widely used outside of Google
Closure Templates are mostly used in projects developed by Google and not in projects by third-parties. As such, it's unlikely for further versions to be released or for changes to be merged.
