Ranked in these QuestionsQuestion Ranking
Pro Open source
Couchbase and Couchbase Mobile are open source and released under the Apache License.
Pro Easy to implement N1QL queries
Pro Ability to run ad-hoc SQL like queries on realtime big data
Couchbase N1QL allows native SQL processing over JSON data with high performance indexing for low latency queries at scale.
Pro Easy sync protocol to mobile devices
The minimal code needed to pull data down to a device
Pro Available on Windows, Linux & macOS
Pro Ability to make predefined fast queries
With Couchbase you can make "Views" of data, which are practically predefined queries which are fetched with an O(1) algorithm.
Con No model mapper for Android
Couchbase does not have a model mapper for Android built-in and out of the box, instead you will have to write your own from scratch.
Con Not Compatible with couchdb
Since version 2 the sync-protocol is no longer compatible with couchdb. This makes couchbase nearly worthless