Azure including their Virtual Machines are a great competitor to Amazon AWS and EC2. I've used both.
Office 365 and Hosted Exchange are a great competitor to Google Apps. I've used both.
Windows Phone 8 is a great competitor to iPhone. I had iPhone 3G, iPhone 4, iPhone 4s and now a Nokia Lumia 928.
Windows Surface Pro (i.e. not RT) is a great competitor to iPad. It really is a desktop/laptop replacement unlike the iPad and again, I've owned both.
Windows 8 had several issues out of the gate. I use it every day and spent the 10 minutes necessary to learn the new interface to get used to it. Many people aren't willing to do that. Vista had even more problems, and Microsoft still came roaring back with a very successful Windows 7. Microsoft is hoping Windows 8.1 does the same thing for Windows 8.
In all of this, the customers win. Expect cheaper prices with increased competition - example being how Amazon just lowered their EC2 pricing by as much as 80%.