Is that this is not about which solution is better. The Article is about the reality of many medium to small shops with small IT departments.... which is that MS WIN2K/2K3 server is being used for the primary big buck expenditure for establishing an Infrastructure in which there is minimal training needed regarding implementation of a solution that provides one stop shopping for said solution. If one looks at many shops, they will see that "out of the box", MS is easier to implement (please note that I didn't mention that they were using correct security or deployment procedures in many places). When they have the basics such as authentication, file/print services, etc..... then the budget gets thinner. For instance, how many people would go with Q-mail if there was an plug-in to tie in with A/D vs. using Open Ldap? Sure one can use "Insight" (which provides the only tool to tie in the email server with A/D). But we are talking about using Linux on the backend to tie in with A/D.
E-Directory costs money also (and plays nicer with Linux), however, I suspect that it will see less and less market share given it's T.C.O. vs. Microsoft's (and mindshare is almost non-existent within many I.T. shops). Surely people can see past what is better and will acknowledge the reality which is that Microsoft has won the Directory Services battle at many companies. Given that, having the option to tie in low cost solutions such as Q-mail with Active Directory regarding Address lookups and authentication will be the first step towards keeping Exchange, SQL, and other Microsoft offerings out of the enterprise. I am a Microsoft support engineer for my company and even I am sick and tired of the Software Assurance / Licensing costs associated with Microsoft's products. But Microsoft purposely makes Server Software cheap and easy to implement, and goes in for the kill regarding exchange, sql, IIS, etc.
How about the Linux Pundits find religion as the author states and realize that Microsoft will almost always be tied in regarding providing A/D (and that it would be best to either provide an Open Source solution or develop products that tie in with A/D).
There is a saying..... "In I.T., there is no right way to do it.... only the way that meets expectations of the user community and management. There is no such thing as I.T. Nirvana where everyone does things the way they should be done." Best for some people to get off their polyana soapbox and accept reality. And that is where this author was trying to take this article.