I've worked with them as a consultant, and am currently bidding on another project with them out of Ohio.  I have utmost respect for everyone from Microsoft.  I've worked with everyone from the Program Manager of ASP.NET to the SQL Server 2000 design teams, and everyone one of them have been exceptionally talented, affable, and [mostly] humble people.  Those at Microsoft are without question top of the industry, but if you read any /. literature nonsense you'd expect just the opposite.
I have a few friends that work for Microsoft, and some of them are in so-called evangelist roles.  They have fantastic stock options programs (not sure if this is applicable for everyone) and a positive working culture very conducive to creativity.  
All that being said, would I work for them?  Not now at least.  I'm at my peak and earning far more than I could at Microsoft, but when I'm in a position where I don't have to work I'd like to work with Microsoft.  Microsoft would have to be for the love of the work, but right now I'm securing my financial future.