Did you also consider Couchbase Lite? I'd be interested in your decision making.
Cb lite was complicated since it needs a native plugin rather than being just js. That wasn't too bad.
The thing that put the nail in it for me was all the setup on the server side with sync gateways, multiple databases that then sync with one another, etc etc.
couchbase-lite apparently also works with couchdb (protocol compliant) and cloudant.
I am currently working at a gig where the use of couchbase-lite with sync gateway and couchbase are required for a project.
I've upvoted davidbanham's comment because that seems like a more insightful answer to your question.