When you do so little tasks (compared to a laptop) and are spoon fed features and programs through the app store...you better be fast and work flawlessly.
"On a Windows based PC, I’d still be waiting for Outlook to get done doing its thing or dealing with some Windows update that came in during the night that rebooted my machine."
I hate to burst his bubble, but Windows 7 is a pretty fast OS.
This article sounds like it was written by someone who couldn't understand how to do the most basic tasks on windows 98 (aka most Mac users) and has switched to the Mac ever since. His opinion of windows in ths article is probably based on Windows 98...
I think that a strict comparison to full-fledged laptops or even netbooks will not give you the answers.
Let's look at this device with a reverse-engineering attitude, function from form: it's all screen. The virtual keyboard is sort of awkward, and the physical one is optional. Swipes and other gestures can give you a very immediate interaction, but over a very simplified set of actions. Obvious deduction: this is a device designed chiefly for media and data consumption, not for data elaboration and production. The application installation is locked to a provider-based scheme. All the OS is locked down to the essentials, its interface geared toward navigation, not editing, of documents.
The good points of a laptop/netbook (flexibilty of functionality, universal traditional OS, sheer power, hardware keyboard) are hardly interesting in this light. They add weight and clumsy interfaces between you and the media you have to consume. Working flawlessly is probably not high in the priority list of the typical user.
On the other hand the app store, the browsing experience, the ebooks and itunes shop options, the phone-like interface - that look like limitations from the point of view of general computing - are clearly great if you don't care about generality and you see it as an elegant appliance to access and consume any content Apple will approve and can build a business on.
My take? We're still in the infancy of the device and tablets never gained mass market momentum before. The early adopters are still buying it for the cool factor or because they are Apple feticists. But appliance-like devices will carve their big niche when the dust settles.