Plasma, like all large software projects is not bug free. But all bugs do not affect all people.
There are hardware, packaging, and configuration factors that may escape KDE's control. Indeed, your experience may be specific to you.
That said, you can do your part and dispel any doubts at the same time by reporting concrete, reproducible bugs to
We appreciate feedback and thank all users who take the time to help us locate and eliminate errors in the code.