I'll jump in. I understand why the person you're replying to doesn't want to go into it, because the things that count seem small. The task manager, carried over from Win 8, is great. They took the window management updates in Windows 8 to the next level - now I can quickly snap not just left and right, but I can quickly snap to quadrants, which, on vertical monitors, is so minor but so helpful. There were some file management tricks it did that I can't specifically recall, but I thought 'Oh, that's new.'
I don't think there are any updates to the task bar from Windows 8, but the Windows 8 task bar is definitely my window manager of preference. I run uBar on my MBP, but on Win 8, being able to quickly preview windows in a group, close individual windows, drag up to create a new window... I miss that at work.
They've made a lot of progress updating the icons. There's still crufty Win95 ones in there if you dig deep enough, but the overall look is as unified as it's ever been.
I'm still astonished at how bad fullscreen and multi-display support is on OS X, compared to Windows. I don't know that 10 brings anything new to the table there compared to 8, but 8 greatly simplified things like hooking up a projector, or setting a screen to mirror. In fact, a lot of the things I really like about modern Windows involve WinKey shortcuts - Win+P in this particular case.
I just noticed that I can't have my network preferences open at the same time as my display preferences in OS X. Not a showstopper obviously, just really weird to me. Wonders never cease...
Nichey point: They've made notable improvements to their MIDI stack.