Suggestion: It would be great to have a page on your website that explains why RethinkDB is better than the other prevailing options. Right now I don't know why I'd want to invest time setting up yet another database.
The elevator pitch is: "Mongo's ease of use without the gotchas." We have a nice simple to use query language and quick setup process. But things like analytic queries like map reduce don't lock up the entire database. Our product aims to not be a ticking time bomb of technical debt.