[tracker1]

Mongoose adds a bit to the table. It actually adds schema validation, which mongo doesn't inherently have, and should be part of the application anyhow. I feel that's the biggest reason to use mongoose over the straight mongo driver in many cases.

I've used Mongo in a couple projects where it was a great fit. The scale wasn't huge, but having pre-shaped data for a mostly read scenario was great. I've found that it works really nicely for a lot of situations, and would definitely be a consideration.

I find that document databases work best when your data is read far more than written to, and when you can shape your data structures for simple key reads in most cases combined with indexed searches. I would consider the use of ElasticSearch or RethinkDB in most cases where you might look at MongoDB. It really depends on your needs here.

Riak and Couch offer other advantages, and like anything it really depends. Cassandra is another nice option for larger scalability, but everything has a cost.

Mongo is very reasonable, and to be honest, if you don't need more than a single server for your needs, it's really easy to get up and running quickly, and development tooling is decent enough, and the concepts are pretty easy to get up to speed with.