I personally don't blame Oreilly for publishing books about .Net, because I think customers have the responsibility to choose what they want to support. If nobody want's books about .Net there wouldn't be any market for it. Instead I recomend to sit down for a minute before choosing .net for your technology.
Think history and specially policy of Microsoft. Before Windows 95 there was a tight match between Word Perfect and Microsoft's word processing tools. When win 95 came, also existing Word Perfect became more unstable and Office 95 was released. After that Microsoft have dominated windows word processing tools. Microsoft want's to be leading company in computer technology, but it surely doesn't want to defend it't market share with fair play. One of the main strategies is to break standards and make their own technology to replace the standard. Good example is C#, which syntax and features are pure copy from Java. From the very begining of Java Microsoft's purpose was to make java void, or make it windows specific. Another good example how MS have chained many companies to develope windows only software is Visual Basic. All this aplies to .Net. MS tries to sink java with it, and also make companies more addicted to windows. How many of you think MS will port .Net to *NIX, Mac Beos... systems. We are tolerating all this and even giving our support to Microsoft when we are using their technologies like Visual Basic and .Net.