I was using Raven around ver 1-3. Even it was single node and simple app, we observed stale reads and lost writes so had to eventually migrate to SQL Server. It was really weird reading claims from Oren (expert in .NET space, famous from his great work on Nhibernate and few other frameworks), where his db didn't work as advertised at all (back then build with Esent key/value store + full text search for map/reduce, think it was lucene.net - obviously very broken tech for this purpose). Too bad, was really hoped things were fixed by now, Db has really good programming APIs.

Interesting trivia: there's "raven db done right" - https://martendb.io/ , just an API wrapper around PSQL. Named Marten because thats a natural enemy of ravens:)