I don't have any experience with MongoDB, but I am building an application right now using CouchDB and I've found it to be pretty easy to use -- definitely easier to prototype with vs a relational database + ORM framework.
CouchDB supports ad-hoc queries in the form of 'temporary views'. The downside (and I think a difference compared with MongoDB) is that temporary views can't be used in production since they are not indexed and thus are much slower than permanent views.
I'm developing my application in Python, which has great support for CouchDB in the form of CouchDB-Python (http://packages.python.org/CouchDB/) and CouchDBKit (http://couchdbkit.org/). Using CouchDBKit, it was pretty easy to set up CouchDB artifacts (map functions, reduce functions, design documents) into a nice file/folder hierarchy and write the simple Python glue code to deploy updates to CouchDB via a single shell command.
CouchDB supports ad-hoc queries in the form of 'temporary views'. The downside (and I think a difference compared with MongoDB) is that temporary views can't be used in production since they are not indexed and thus are much slower than permanent views.
I'm developing my application in Python, which has great support for CouchDB in the form of CouchDB-Python (http://packages.python.org/CouchDB/) and CouchDBKit (http://couchdbkit.org/). Using CouchDBKit, it was pretty easy to set up CouchDB artifacts (map functions, reduce functions, design documents) into a nice file/folder hierarchy and write the simple Python glue code to deploy updates to CouchDB via a single shell command.