These two articles aren't really about Active Directory or eDirectory. They're about the challenges people face while migrating large business networks to Linux. That said, I've asked David to explore eDirectory in his next article. If it solves the problems he brings up in these two articles, it's well-worth an article.
As to questioning an author's research or conclusions, that's one reason we have talkbacks enabled. That goes for any author. If you have hard numbers as to deployment rates of one product versus the other, by all means please post them -- but I'm going to need something stronger than opinion.