Yes.
You could argue it's more RAM and battery efficient and more secure. IMO the UI elements/icons/animations look better too. The scrolling/zooming/panning/rotating animations are more fluid and natural when you use a trackpad. As for productivity it depends on if you prefer OS X features like Mission control/spaces or Windows 7's window snapping. The rest like window button location, shortcuts, filesystem structure and such depends a lot on what you're used to.
Other than Windows apps and games, Windows will generally offer better game performance because of DirectX. OS X uses OpenGL instead since DirectX is made by Microsoft and Windows-only. I don't know if DirectX is technically superior to OpenGL or if it's just developers that focus less on their Mac OpenGL port since less people use Macs.
You're right. You COULD argue. No one can force you to be right.
Can't speak for ML but it's well documented Lion couldn't handle RAM properly.
Security on mac is/was (improving but i stopped following the details) far behind windows. You're just less likely to need to rely on security measures "at the moment" due to windows being far more popular/targeted. The major documented cases of people actually targeting the mac over the last 2 years have all been laughable exploits.
Can't say much for battery life but I do believe there is some truth in this, OS X typically lasts longer on a low workload (web/office) but given something intensive both systems should be more or less equal.
I was referring to space feature.
this "can" be done in windows with relative ease but OS X's native support is more convenient obviously. But essentially if it exists, you can probably do it in windows.
This whole thread is basically "is there ANY reason to run windows
other than the reason to run windows" :S
but to sum it up. Applications, Greater Hardware Support, Likely to be used by your school/workplace, In my opinion more "robust", probably some other things I'm forgetting.
I'm not saying OS X is bad but I far prefer windows for just generally using an operating system from day to day, I know my way around it better and the mac interface just seems ridiculous and backwards to me all the time, whilst missing very basic things. I'd ditch spaces any day to have the keyboard short cuts and run command I can quickly pull up in windows. There's no substitute I could find for the mac whereas most mac features have windows substitutes.
That being said, I only just got my first mac this week.
The reason I own a mac is pretty much just native RAW support
/long pointless post.