The ability to use it as an embedded system for processing real time data. This was my first experience with noSql databases and I found them easy enough to learn and implement into our projects at work. Their documentation could be better so that new users don't have to figure something out themselves when they hit road bumps. Also their price structure can seem steep if you're using this mainly for personal project/learning purposes only. We solved most of our issues around dealing with complex real world events and also saved us some cash by not needing expensive hardware just to process large amounts of data that we needed from point A to B very quickly (i.e., stock market trades).