Is anyone else using Couchbase? I'm evaluating it for a project with a mobile component and Couchbase Mobile with its automatic syncing seems like a great solution. Would love to hear peoples thoughts.
Of course there are smart people at Couchbase too, I'd just suggest giving Cloudant some serious consideration.
Couchbase was designed for write-heavy applications and built with clustering in mind from day one. CouchDB was designed for read-heavy applications where versioning and replication are important. Cloudant, by way of their BigCouch product, has done a lot of great work on clustering for CouchDB and all that work is slowly making its way into CouchDB core.
If you want the comparison of CouchDB vs Couchbase from Couchbase directly, you can read that here: http://www.couchbase.com/couchbase-vs-couchdb
In my opinion, the next closest NoSQL DB to CouchDB would be ElasticSearch.