Yes there is. I have no problem with people saying Windows 10 isn't good, even if I personally think it's good. The "goodness" of an operating system is pretty subjective.
I do have a problem with people calling it barely usable, which is a much more objective (and incorrect) statement.
There's a large gap between 'usable' and 'good'.
They destroyed the consistency of their interface (combined desktop/mobile anyone), and added a lot of cruft that literally nobody who's used Win 7 needs.