Nope, not what you are thinking- not a security rant, not a dumb reaction to something, not product quality, not even pricing or licensing. It is how they treat the people responsible for their success- the admins in the trenches who make Windows work, the partners and developers- and their odd logic about getting your hands on a copy of Windows 7.
I have been a TechNet subscriber for many years, I can't imagine running a Windows shop without a subscription. Others look on their MSDN and Action Pack subscriptions similarly. None of us get a copy of Windows 7 yet, but we can play a game of begging to get a copy- anyone can who finds the right links and is willing to play the game. Sure, Microsoft will say they want people to provide feedback and contribute to the product, and they want control over distribution of beta code. Nonsense. The people so dependent on Microsoft technologies that we are willing to pay for the content, that's who should get their hands on early semi-public beta software, because we will make it work, and the more advanced look we get, the better job we will do of making it work.
Windows 7 is getting some good press, and it should- it is what Vista should have been. Stuff works. Stuff that doesn't work responds to the same fixes developed for Vista. It is lighter, faster, and less annoying, but without losing the usability enhancements Vista brought. I can confirm some of this because a friend bent some rules to get me a copy- which I can't use much longer because I can't get a license key. That means I won't be able to do as much pre-release compatibility testing with key vendors' products before launch, nor document interoperability, or even tell people what I really think about the product. This also means I won't have confidence in the product for longer after it is in the wild and will probably have to give the advice we have all given forever- "wait for Service Pack One before deploying", instead of "the beta process was so thorough, it's safe to start limited deployments". That is stupid, and a symptom of what is wrong with Microsoft. (Microsoft is one of those companies, you know several of them, full of great people who rarely let you down- but as an entity is most likely to disappoint you).
The security implications are clear, too. For all it's problems, Vista is more secure than its predecessors, and Windows 7 should be more secure still. The faster we get people off of older versions of Windows the better for all of us. Vista was a disappointment; Windows 7 has promise, but if the roll-out is fumbled we'll continue to see XP, 2000, and even older systems out there, sitting ducks for attackers.