Ahh, I have been doing a lot with MongoDB lately. Are you going to be doing a lot of free text searching? If so, look at ElasticSearch instead.
What tech stack will you be using? Node?
So, IIS backend then. How tied in are you to that stack? Given the choice I find MEAN to be the perfect Mongo stack. Drop in Mongoose to cover your model as a Mongo ORM and you are gold.
I’ve heard a lot of good things about RavenDb but it’s also a very opinionated system. It leads you down by the nose to good usage.
Also, checkout Highway Framework. It’s a nice abstraction layer that allows you to swap out DB implementation with ease.
Its ok is mongodb