Original author of OrbitDB here. Thanks for the interest and discussion so far!
We just released a new version after months of hiatus, bringing a lot of stability, performance and new features to OrbitDB. The main new, big feature is the write-permissions. See the updated repo at https://github.com/orbitdb/orbit-db and the Changelog for v0.18.0 for more information.
We also added a brand new Getting Started Guide that should answer many of your questions. As for the underlying CRDT that OrbitDB uses, see ipfs-log (append-only log CRDT) or the Counter database's G-Counter CRDT. The first is a operation-based and the second one is state-based.
To get an idea "how it looks in an app", you can check the TodoMVC Example or the "browser demo" (source code).
OrbitDB doesn't currently have a collaborative text-editor CRDT, so you're better off with Peerpad for that. That said, we'd love to have a text-editing CRDT in there and it should be straight-forward to integrate, so if anyone's interested to implement it, I'd be more than happy to help!
If you have any questions, feedback, suggestions or problem, would highly appreciate reporting them in https://github.com/orbitdb/orbit-db/issues