Do you use data mappers with MongoDB?

I've been diving into MongoDB with kind help of MongoKit and MongoEngine, but then I started thinking whether the data mappers are necessary here. Both 开发者_Go百科mappers I mentioned enable one to do simple things without any effort. But is any effort required to do simple CRUD? It appears to me that in case of NoSQL the mappers just substitute one api with another (but of course there is data validation, more strict schema, automatic referencing/dereferencing)

Do you use Data Mappers in your applications? How big are they (apps)? Why yes, why no?

Thanks

We are running a production site using Mongodb for the backend (no direct queries to Mongo, we have a search layer in between). We wrote our own business / object layer, i suppose it just seemed natural enough for the programmers to write in the custom logic. We did separate the database and business layers, but they just didn't see a need to go for a separate library. As the software keeps evolving I think it makes sense. We have 15 million records.