Another CouchDB fan here. CouchDb's mango queries are implemented as Erlang map functions under the hood. Users now can get the speed of Erlang and the usability of Mongo-like query syntax.
Thanks for the CouchDB feedback guys! I am curious to try it out. I should have been more clear, I was actually referring to Couchbase (https://www.couchbase.com/) not CouchDB :) Very unfortunate naming conflict considering they are both JSON document stores. Is there something about the word 'couch' that I'm missing?
From my experience with Couchbase though, I would recommend it to others. They support SDKs in many languages, have decent documentation, and the server has performed well for us. The query language 'N1QL', tries to emulate SQL syntax, and I found it nice to work with.
Couchbase was a commercial CouchDB spinoff product, co-created by the programmer who created CouchDB. Much of the API is (was?) the same, but where possible, Erlang was exchanged for C++.
It also has a built-in, in-memory cache layer, which CouchDB doesn't have.
From my experience with Couchbase though, I would recommend it to others. They support SDKs in many languages, have decent documentation, and the server has performed well for us. The query language 'N1QL', tries to emulate SQL syntax, and I found it nice to work with.