or - mongo is great for some problems and not so great for other problems. if there is one thing you can figure out hanging out on HN long enough - it's cool to hate on mongodb
Tens of thousands of computer geeks all randomly chose to hate a product. Clearly a coincidence or unlucky alignment of stars, nothing to do with said product, of course.
Lover: MongoDB is so much faster and easier than old school SQL! Hater: It's fast and easy because it doesn't check if it's written data correctly, which leads to corrupt data. Lover: Well you could always turn on the write lock. Hater: If you turn on the write lock, it becomes slower than normal SQL databases. Lover: Well you're just trying to use it the same way you use SQL. MongoDB is great for some problems and not so great for other problems. Hater: What problems is MongoDB better at solving?
And then that's the end. I've never heard a convincing use case for this thing. If you can change that for me and give me one, I'd be delighted to listen.