We use MongoDB in several capacities on several projects: A cache/ speed layer for content distribution worldwide (relying on replica set across data centers),

We use MongoDB in several capacities on several projects: A cache/ speed layer for content distribution worldwide (relying on replica set across data centers), an event source for customer loyalty and profile management, and as a backend for an e-commerce style customer facing web store. In each of those projects we leveraged several mongo features that were well suited to the problems we had. Our mongo clusters have been remarkably stable and work very well. Our scale has not required sharding at this point. Our QPS and write rates have been well within the design SLA. We did have to periodically analyze query performance and apply index and or query syntax changes, but other than that didn't encounter any issues. The biggest wins for us was time to market and flexibility: Compared to the RDBMS counterparts, we move faster, resolve issues faster, and deliver web pages faster. The negative publicity has been "in the noise" and typically reflected more negatively on the generators of such rather than the product itself.