Every developer I've met in person prefers Mac/nix for any situation in which Windows development isn't mandatory.
Am I looking at a biased sample? Maybe, maybe not. I mostly operate in the web development world, but I know developers of all stripes. And none of them prefers Windows.
That being said, there are developers and companies who prefer to develop for MS platforms as a business decision. I.e. they want to target that market. But that doesn't mean they actually prefer developing on Windows. It just means Windows is imposed on them by their business choice. Analogously, I don't care much for Xcode or Objective-C, but I still write IOS apps because it's an important market.
I prefer Windows. I work in a cross platform shop, my code needs to run on Mac and Windows but unless I'm trying to track down a Mac specific bug I'll do the initial coding on Windows. For what I am trying to do (cross platform C++ development) Windows has better tools. Visual Studio has a better C++ compiler than Xcode. Visual Studio has a much better debugger than Xcode. Beyond Compare is Windows only and I haven't found anything that matches it on Mac (please let me know if there is something that's as good on Mac). Source Insight is only available on Windows - I know that SlickEdit is available for the Mac but I much prefer Source Insight.
All my personal opinion that applies to my particular circumstances only.
While dtrace is a wonderful tool, it is a little disappointing that when Apple adopted it from Sun that they modified it so that setting a simple flag in your code (P_LNOATTACH) will prevent it being traced. http://dtrace.org/blogs/ahl/2008/01/18/mac-os-x-and-the-miss...
Am I looking at a biased sample? Maybe, maybe not. I mostly operate in the web development world, but I know developers of all stripes. And none of them prefers Windows.
That being said, there are developers and companies who prefer to develop for MS platforms as a business decision. I.e. they want to target that market. But that doesn't mean they actually prefer developing on Windows. It just means Windows is imposed on them by their business choice. Analogously, I don't care much for Xcode or Objective-C, but I still write IOS apps because it's an important market.