It works fine if you just use it properly. For example
quote:
different name of the author (the most common)
that one occurs if you select part of one post but then click the quick quote button of another post (made by someone else). The selected text will be in the quote, but the name will be from the author of the post of which you clicked the button.
quote:
sometimes only appears part of it.
That happens if you (accidentally) select a part of a post and then press the quick quote button. Even if you have selected something and then click outside the selected text to undo the selection still only that part can appear in the quick reply box.
quote:
and today
I refer to the paragraphs above: you selected that part (the IP logged text and such) as well, hence it was also quoted.
As you can see, there's nothing wrong with the quick quote feature