- the UI may be noticeably slower on some systems
- it is more difficult to avoid using a Microsoft account
- the task bar cannot be moved and customization is more limited
- some right click menu options are hidden behind an extra click
- the start menu is different. More like an app drawer than previous versions.
- some long depreciated features (like ungrouping taskbar items) were removed.
Personally none of that bothers me, but everyone’s usage is different.
Oh, and the worst issue is the hardware support. It requires a newish processor and TPM (or equilivant)