Mongo is actually great for very small datasets. But they sell it as a clustered solution (mongodb.org is currently featuring a giant banner that reads, "Agility, scalability, performance. Pick three"), so it's fair to judge them on that.
I agree, but I'm getting the sense that some people (including the OP) are using the CMM article to claim that Postgres is more reliable. Postgres doesn't have this kind of clustering feature at all. Not a fair comparison.
