Solely looking at it from a mobile database point of view which is going to synchronize with a remote server,assuming it doesn’t really matter if it is relational db or NoSQL,
what would be the better option to go along with?
Client platform is android
My vote would be for CouchDB.. The reason being, as NoSQL, it has good number of advantages. More than anything, you can make the user’s data available offline.
Just in case you want further info on usage of CouchDB, I would like to request/suggest you to go through this, this and this.