Yeah, I can agree with that. A lot of their claims of scalability and benchmarks aren't lies, but they come with a lot of asterisks. I know in my last job we used both mongo and (mainly) microsoft sql server, and frankly, I enjoyed developing against mongodb way better, but if I needed something to be consistently fast, there was no question I'd put it in sql server. (Mongo's query speed can be really variable, and the tools to diagnose query planning kind of suck compared to more established databases)
