I think we will be using a few dialects for Joda time and layout decorator. We will also likely write some of our own to encapsulate some display logic. This leads me onto some of the (minor) grievances we've had with thymeleaf - only because you asked :)
* Parses templates with XML parser - HTML5 has elements that you wouldn't normally close. Thymeleaf will do tag balancing with a LEGACYHTML5 template mode, but it doesn't feel quite right
* BEM css naming syntax breaks pre-processor - raised issue https://github.com/thymeleaf/thymeleaf/issues/249 * The name spaced attributes start to clutter the markup making it difficult to read. It can also lead to adding extra spans and divs from time to time
* Creating dialects is far more complex than grails tag-libs ever were, and more difficult to test - element of learning curve with this one I suspect
Like I said, nothing major but they guys felt like they were battling with it, as opposed to it making their lives easier.
Yeah we tried handlebars, but really missed using the decorator pattern, although i think there is some support in the java implementation we needed to pass variables around which we weren't able to set. We couldn't quite make the leap into logic-less templating.