Gosh, so difficult to have to face fanboism every time an OS is mentioned. It's become pathetic.
Let me try to (attempt to) explain:
What the MS person meant is that the kernel (also used in Windows Server) which powers all kinds of hardware including servers, is much more stable. Do you see a lot of OSX-powered server machines running anything else than ShoutCast?
I'm running Win 2008 file, intranet, etc. servers and have not rebooted once in almost 2 years. I don't see it needing any reboots in the coming years either. Now that for me is stability, so I accept his point totally.
Now obviously if you consider client machines for home users etc. there are issues with hardware, rogue software, etc. So of course the systems there are less stable.
But to be fair, I bet if OSX were to support all kinds of hardware, it would be much buggier than Windows 95 tbfh. Quality is directly proportional to dollars spent for testing. Supporting one base (and still getting it wrong sometimes) is one thing, supporting thousands is another.
So please try to keep a higher level, understand why things are where they are right now and don't be a fanboi.
I for one welcome that Win 7 is more Mac-like UI-wise.
But to be honest I'm very glad it's not anything like a Mac in everything else.