Is Nibbana joyful or not joyful? I have noticed that it seems Nibbana has been described as "the peaceful". 

I have had the impression that Nibbana is neither joyful nor delightful.

Is my impression correct?
OP: I have noticed that it seems Nibbana has been described as &quot;the peaceful&quot;.
Nibbana is peaceful of blissful because it is not dependent on sensations/feelings.
The whole Shere of sensation regardless if it is present, unpleasant or neutral is unsatisfactory (dukkha).

pleasant feeling is pleasant when it persists, painful when it changes;
painful feeling is painful when it persists, pleasant when it changes;
neutral feeling is pleasant when there is
knowledge of it, painful when there is no knowledge of it.

Cūla Vedalla Sutta
OP: I have had the impression that Nibbana is neither joyful nor delightful.
In terms of sensations, this is not pleasant, unpleasant or neutral. But since is it not dependent on the sensation it is not unsatisfactory.