As a small-time IT Manager (the company whose infrastructure I manage does ~$100MM revenues worldwide) I can tell you that this blog post is misleading at best.
Apple does everything you can think of to discourage its' products from entering the enterprise. I have 17 macs, running 10.5, 6, and 7, and they are a farce from a management perspective.
Oh, wait, also from a functionality perspective. And, most importantly, from the perspective of available applications.
To paraphrase your god Steve, with whom I once had a personal email exchange, software is the most important thing. Software is what matters.
And macs just don't have software.
ERP? Not really
CAD? Not really
Office? Pain and suffering
Joining a domain and accessing services? Like a trip to the dentist for my users every single morning.
Management? They are harder to manage than a 1990's Windows domain.
The servers are beyond a farce. The servers are well into the absurd, and I'm glad they finally stopped referring to them as servers. They truly are just a set of cheesy services overlaid on an overpriced desktop.
This blog post took away most of the remainder of my respect for MacRumors. It's clearly owned by someone who owns a lot of Apple stock and has an agenda. Don't believe the hype.
PS I was a die-HARD mac fanatic until I had to manage them in the enterprise. I took this job specifically because I got to manage mac clients and XServes, which I thought was a dream. Holy crap was I wrong.