It's fine if you're an average user with modern widely used hardware, and standard requirements
Not so much if :
Your hardware is unusual
Your hardware is old
You want to do something odd, or work in a non approved Microsoft way
After initial issues with hibernation with my work Windows 10 system, updates have made laptop based Windows 10 working pretty solid. I haven't played much with WSL, but Microsoft has to be applauded for it.
For home in a moderately complex configuration there are a load of issues
Have older monitors? Windows 10 is not entirely happy with KVMs
Old hardware? Recently had to re-install Windows 1903 from scratch because an X-Fi Titanium absolutely Will Not Work on a 1909 system that's had various cards installed over time, even after driver re-installs, driver cleaners etc.
The mess of control panels in win32 and UWP format, both of which are required as mentioned by others.
The graphical boot manager, also used in Windows 8, sucks majorly. Revert to the previous one, please.
Automatic driver installs are a *huge* pain if it will break your system configuration. I've had to install with a network connection removed to stop driver updates.
Windows Mixed Reality can break badly and is nowhere near as seamless as Oculus
It's impossible to identify disks during install without selecting a command prompt and using diskpart, at which point a reboot is required to return to the install! So, you have nine disks in a RAID controller, but no idea which one to select.
It'd be nice if HyperV was a little less limited, especially easily assigning serial ports to a VM, although I realise this is a minority requirement.
Having said all of the above, and despite the fact I'm trying to move everything except some gaming and VR towards Unix, Windows 10 really is as mentioned a solidly engineered product. It copes with practically no issues with disks in a RAID JBOD configuration, something that makes almost every other Unix scream. My complaints are somewhat oriented to poor driver quality (I don't know if I can blame Creative Labs for the X-Fi driver issues I've had, but I definitely can blame AMD for their deeply shitty Vega 56 drivers which *STILL* won't load their control panel if the graphics card isn't set as primary in Windows)