I would say the drawbacks for Windows 10 specifically are
A lot of people have an issue with the forced updates although Microsoft has been relaxing that in recent and upcoming releases including the ability to defer updates up to 35 days on Windows 10 home (personally I'm glad they are forcing updates as many home users tend not to patch their systems).
Windows 10 is a complete rework of most of the underlying systems (good and bad). Good in that Microsoft finally gutted a lot of the legacy code which (bad) makes legacy software less likely to work.
Otherwise I'd say Windows 10 is superior to it's predecessors.