Couchbase is great but expensive

While it has some great capabilities, if the developers don't have the n1ql knowledge or understand how to properly connect to the data, there can be very unique issues that are hard to identify. I recommend free online training sessions for developers who use this that ends with a certificate qualifying them to develop to it. This would really help the CB database Support team.

Obviously, it's not well suited for anything transactional. It's also not greatly suited for upgrades or patches without turning off auto-failover. It is well suited for metadata databases and front end fast data retrieval.
It is relatively easy to deploy without training but not intuitive enough to set it up with best practices without pretty good working knowledge of the DB and all its settings and terminology.