Took a look at the code. It's built with Backbone.js!
The site is way faster now, despite having more stuff going on, just because half the codebase is no longer trying to hack around the parts of JMVC we didn't need.
(Marionette is a great project though!)
Edit: One tip for you as well. I noticed that you're using "#!" in your URL routes. You probably don't want to be doing that these days -- either just plain "#" works, or pushState with hybrid server-side renders if you want to be indexed by search engines.
pushState is somewhere on the backburner...