I love all platforms but I am also well versed in all of them. Very few people can honestly say that 
Peace
MrTwo
I think MrTwo's point about "getting work done" is legitimate, reasonable and well founded...based on my experiences with both hard and soft real-time kernels and the internals of HAL, NT, RSTS, RSX, VMS, Sun-OS, OpenOSF, Linux, VRTX, VxWorks and many others.
I enjoy dabbling in technology and for others similarly inclined some of these links may be interesting:
Hard Real-time Windows NT - RTX is designed from the ground up as an optimized extension to the Windows operating system; it is not a RTOS ported to Windows. RTX provides precise control of IRQs, I/O, and memory to ensure that when a particular task needs to execute, it happens on-time, every-time. By operating in Ring 0, RTX ensures high performance right out of the box, supporting sustained interrupt rates of 30 KHz with an average IST latency of < 1 microsecond.
http://www.vci.com/embedded/products.aspx?ID=70
The Leading Experts in Embedded Software Development
http://www.ghs.com
Continuous Availability Mission Critical 99.999% Uptime:
http://www.stratus.com/products/ftserverwseries/index.htm
http://www.marathontechnologies.com/Continuous_Avail.html
Low-cost embarrassingly parallel Unix super computing:
http://www.beowulf.org
http://sourceforge.net/search/?words=beowulf&type_of_search=soft
NYtimes 11/27/05: Designer of Supercomputers Leaves Cray to Join Microsoft - Microsoft announced two weeks ago that it planned to introduce a new version of its Windows software for scientific and engineering users, and that Mr. Smith would be involved.
http://www.isnaini.com/2005/11/27/nytimes-designer-of-supercomputers-leaves-cray-to-join-microsoft/
In the end though, it all comes down to choosing the right tool for the job...no need to try and dig the foundation for a house with a hammer or try to frame the house with a backhoe...it's just a matter of understanding the problem and choosing the best tool for the job.
-jmho