I use it often and love it actually. Mongo + Express/Restify is my default for most of the APIs I build. I usually add in Redis and RabbitMQ (as a caching layer

I use it often and love it actually. Mongo + Express/Restify is my default for most of the APIs I build. I usually add in Redis and RabbitMQ (as a caching layer and queue respectively), and I've never had any problems. It may be that my projects are particularly well-suited to json docs and indexing, so perhaps I'm biased. Most of my APIs are consumed by single-page-applications like Angular, which already structure their data as json collections. So using a json-store (for me) makes things like 2-way binding a breeze.