The reason we use a document based datastore is that it is easier to think about conflict resolution, and it maps more easily into how JavaScript represents data in the browser. It is common for large-scale eventually consistent systems to use document based stores instead of RDBMS.

We also are big fans of testing, and we will have a better answer to how testing can be done. We currently use Mocha, which is a great test runner for the server and the browser. All of our frameworks are still quickly iterating and adding important features like this.