Anecdotes like the one from the article that ended with "The one thing that didn’t flinch was MongoDB" don't convince me one bit. When something else between the end user is a bottleneck it would be silly to assume that is the only problem in the entire system. Who is to say that if the load balancers hadn't been configured differently, or higher spec'd that their MongoDB wouldn't have become a smoldering crater?
While anecdotal evidence is always suspect, remember that the case in the article is MongoDB's optimal use case. That being of being extremely read heavy (There is no indication that they did more than one write that day).
