The Windows kernel really isn't that great by modern standards, neither codewise nor architecturally. And yes I know a lot about it.
There's a LOT of weird stuff lurking in there, and a lot of features they've added in recent years just doesn't work properly at all (anything uwp related...). Even the basics of how you start another process have turned into a labyrinthine mess. Then you have things they never fixed like the totally unhelpful NT file locking semantics that regularly break apps that work fine on UNIX.
NTFS is supposedly a nightmare of tech debt that uses SEH for control flow, yet their attempt to move Windows to a new ReFS stalled and failed. Note: Apple managed this with APFS and Linux distros have routinely introduced new file systems.
COM isn't a part of the kernel but is the same situation - incredibly complicated and has not been evolved well. Lots of failed rebrands, attempts to rejuvinate it that actually made things worse.
Within its own rules, yeah, it's pretty great. Very high performance, huge feature set, everything is configurable and transparent, relatively non-buggy, clean code, runs on everything.
If you want stable driver APIs that allow you to distribute hardware support with the hardware, keeping that investment proprietary, then obviously no it's crap, and that's a pretty important use case.
If your hardware has good driver support in-tree though, then Linux is hard to beat these days. It just gets so much more investment than the NT or Darwin kernels.
There are a few places where Darwin is ahead especially w.r.t. code signing and sandboxing. I can't think of anything that NT in particular excels at though.
Driver guard, safe kernel, userspace graphics drivers, Xerox PARC/Oberon like workflows between kernel and userspace frameworks, setting the rules where graphics APIs are going (DX drives, Vulkan follows),...
Mantle was just a PC API based of how game console APIs work, like DirectX on XBox.
As for Oberon, there is enough material out there.
Suffice to say how Powershell integrates with .NET, DLLs and COM, enabling OS and applications scripting, pursue of safer approaches to OS system programming instead of yet another UNIX clone written in C.
There's a LOT of weird stuff lurking in there, and a lot of features they've added in recent years just doesn't work properly at all (anything uwp related...). Even the basics of how you start another process have turned into a labyrinthine mess. Then you have things they never fixed like the totally unhelpful NT file locking semantics that regularly break apps that work fine on UNIX.
NTFS is supposedly a nightmare of tech debt that uses SEH for control flow, yet their attempt to move Windows to a new ReFS stalled and failed. Note: Apple managed this with APFS and Linux distros have routinely introduced new file systems.
COM isn't a part of the kernel but is the same situation - incredibly complicated and has not been evolved well. Lots of failed rebrands, attempts to rejuvinate it that actually made things worse.