One advantage of MS over Open Source
A lot of people will probably not agree with me but I think the quality of MS products is pretty good. If you want to know how serious Microsoft is about quality have a read of this article. It will give you some insight in the testings of Whidbey and als makes clear what testing on an industrial scale is.
Whidbey is just an example. I guess they have these test scenarios for every product. Can you Imagine how many testing is ging on at MS ?.
My guess is that Microsoft will move on and will continue to be a leader in the IT industry for decades to come. I don't think the open source community can make such an investment in new products. That's why Microsoft will continue to be a leader and the 'Open Source field' will be a follower at best.... If they can keep up with Microsoft's current pace......