In particular, Hadley sees Apple's advantage dwindling in terms of software and UI: "what is left? Better hardware? Perhaps. More software selection? Certainly not," but what I think Hadley is not accounting for is that 'more' does not definitively equal 'better,' not by a long shot. I'll admit it's been years since I've truly sat down at a Windows machine and worked on it or searched for software to do one task or another, but an ongoing discussion involving software quality, innovation and accessibility eludes to the possibility that a little consumer fish isn't always at an advantage in a massive, diluted software pond. In other words: there are reasons why Apple is praised so often for including things like iLife with their machines (which still stomps commercial Windows counterparts), and why the typical MacUpdate-savvy, RSS-aggregating Mac users are often asked where and how to find any decent software by their Windows-toting brethren.
The most significant element of Vista Hadley steamrolled over is the truly massive and fundamental changes Microsoft is making to Vista's UI (whereby 'changes' could be interpreted as 'taking a sledgehammer to'). I'm not talking about just the Transparency Everywhere™ technology (that's an entirely separate conversation): this is about the radical redesigning and non-standard placement of traditional, basic elements like menu bars. Remember how much of an outcry ensued with Windows XP's slightly redesigned task bar and Start menu? Office dwellers were hurling themselves out of windows (and of course, forgetting to log out before doing so), claiming the apocalypse had arrived. While the Office 2007 camp has been receiving some eventual praise for the new 'ribbon' interface, I dare you to look at Office 2007, Vista's Windows Explorer, Windows Media Player 11 and IE7, and try to claim their UIs were forged from the same standards playbook.
Take a look at this Microsoft blog with examples of how much Vista's new UI has shifted, and note the non-standardness of everything. Some apps now have 'button bars,' while others have been stripped of a menu bar entirely. How anyone could consider this as looking "very similar" to Mac OS X or even 'understandable by the common user' is beyond me. This is a lot worse than Vista merely being "ugly" - it's like someone taking a shotgun to the Windows UI, duct-taping the results for review and Ballmer slapping on his gold-plated stamp of approval while polishing his two left feet.
Of course, from the guy who's trying to lay the OS down to sleep, I guess this all makes a little more sense. Let's just hope Mr. Stern is never actually faced with his 'desert island' decision, since after all: it still is a decision.