I already use Coredata for local persistence. I use Mongo behind a REST API for data storage.

So what would CouchDB give me? Offline data sync? That's useful but wasn't hard to implement on my stack.

The reason I didn't use something like CouchDB is the time saved up front probably wasn't worth the cost in optimizing/debugging. It's just much harder to track down and fix bugs and address bottlenecks when relying on a large library designed for general use cases to do much of it.

I'd also have to buy-in having CouchDB on my server.

In this case I'm pretty sure I made the right decision. If the requirements were less rigorous, CouchDB Orr something similar might be better.