Oz/Mozart is pretty cool. Last time I looked at it I thought it was mostly a teaching language. Have there been large scale applications built with it recently?
I don’t think so. As far as I understand it’s intended as a teaching language.
I was blown away when following along with the edX course  and the textbook ,which demonstrates you can have all different programming paradigms in the same language, depending on which primitives you add. That clarified quite a few things about PL fundamentals for me.
 https://courses.edx.org/courses/LouvainX/Louv1.1x/3T2014/course/ and https://courses.edx.org/courses/LouvainX/Louv1.2x/4T2014/course/
I ran a web service for a while written in Mozart/Oz, using the Roads web framework. It worked pretty well but I hit some scaling issues with the runtime - I hit limits with incoming sockets due to use of ‘select’ in the runtime vs epoll/kqueue/etc. I still use Mozart/Oz occasionally. I’ve been working on porting the runtime of the 1.3.x version to 64 bit in this branch so I can continue using it.