Except that those are not the words on a libelous, frustrated competitor. I've seen these claims validated over and over again both by posts on HN but also people I trust that have worked with MongoDB under load.
Performance benchmarks stop being meaningful when you realize that you can't fix the problem you're having without committing to a system-wide shutdown of unknown duration.
The main point that the author makes is that the creators of MongoDB do not follow rigourous practices. If this doesn't bother you, please go right ahead and use anything you wish.
In most case, I think 10gen will be able to dispute false claims.
With regard to nomongo's post, 10gen can check their record and say whether they did or didn't have a customer with premium support account with similar use case and issues. 10gen can also counter such complaints with testimonials from customers with similar use cases.
But note that nomongo's post is not about individual issues but about his concern that 10gen's priorities are misplaced which he should have wrote first instead of last. Rest was just about how his concern came about. Current status of technical issues he experienced are irrelevant to his concern.
