Joe's response is perhaps a little pro-Microsoft (you can't really blame him for that--he does work there :-) but the essence of his response rings true; there's nowhere near enough factual data in the OTN article to make a balanced decision one way or the other.
To be fair to Sean (the author of the OTN article), it does say "Opinion" across the top of the page and the byline is "One developer's view of the pros and cons of the two most popular means of building web applications", but it's easy to forget those once you're into the article.
I don't want to get caught up in a comparison myself so I will say that a good systems architect will take into account a wide range of factors before arriving at a decision about what is the right combination of tools for the job, and that Joe's response reminds us that projects for really big customers tend to have different non-technical criteria to what I'm going to call the "typical" PHP customer. By non-technical criteria I mean things like business or political concerns--things like corporate mandates for technology choice, considerations based on the skill-set of a possibly very large existing IT staff and so on.
In plain english, it may cost next to nothing to employ PHP developers to build an application, but it may cost a small fortune to "re-tool" the support infrastructure to be able to effectively deploy that application in an exclusively Microsoft/Windows environment. In this situation PHP is not the better solution, even if it would have gotten the job done in less time and with fewer lines of code.
The point of this blog entry is to encourage people to think a bit harder before they sit down to write. You should try to qualify your observations by talking about the environment and other circumstances that apply to situation and then back it up with some factual data. This will turn anecdotal stories into a useful technical resource.