Is Nibbana joyful or not joyful?

Words aren't really meaningful unless they correlate to something connected to your sensory perception.

Having experienced higher states I can tell you that it's definitely joyful rather than peaceful...I think of peaceful as more like deep relaxation and joyful as more like happy with high energy.

MN 59 categorizes different types of pleasures (each one higher):

1. Sensory pleasures
2. 1st jhana
3. 2nd jhana
4. 3rd jhana
5. 4th jhana
6. Infinite space
7. Infinite consciousness
8. Nothingness
9. Neither perception nor non-perception
10. Cessation of perception and feeling

The cessation of perception and feeling seems to be connected to arahantship or nibbana or almost like the same thing.

Based on the suttas nibbana/arahantship/cessation of perception and feeling is the highest pleasure.

But I guess you would have experience it yourself to know...all I know from experience is that higher states resulting from destroying negative unconscious impulses is joyful beyond what you can imagine.

If someone really experienced nibbana they should be able to describe it in detail.

From my experience the highest state I've experienced was when the energy went above my forehead, above the top of my head, and even further I felt high energy, confident, fearless, unstoppable, like nothing is wrong...it is a joy like no other.

The arahant has their fermentations ended so to inspire fear in an arahant is impossible!

If having difficulty making progress then best to generate good kamma through the practice of metta (loving-kindess)

"Bhikkhus, whatever grounds there are for making merit productive of a future birth, all these do not equal a sixteenth part of the mind-release of loving-kindness. The mind-release of loving-kindness surpasses them and shines forth, bright and brilliant." (Iti 27)

Best to shine loving-kindness as opposed to negative emotions like anger, fear, sorrow.

On Nibbana

"This is peace, this is exquisite — the resolution of all fabrications, the relinquishment of all acquisitions, the ending of craving; dispassion; cessation; Nibbana."

— AN 3.32

Its essentially peace within your being .In Your experience of joy or sadness you are detached meaning not possessed by the experience .It doesn't mean that you are indifferent or passionless but truly alive ,cooperating with the experience ,being with the experience ,where there is nothing but experience ,ceasing to cause anything or interfere in your life process, because with every need to cause there is nonacceptance of an experience .Thus in Nibbana you simply are .

Its important to realize that you don't view Nibbana as a goal that your ego needs to achieve You don't gain anything from Nibbana because you become empty from all your conditioning and your ego with all its accumulations disappears.You let go of all the attachments including that of the body, you let yourself happen like you let a flower bloom.

Yes.

Whatever word you use to describe it, it will miss the mark, as Nibbana is free of concepts, perceptions, judgements, etc. If you label it "peace", that is based in your perception of peace, which cannot exist at Nibbana. If you label it bliss, that too misses the mark. It may be more accurate to say, "after the experience of Nibbana, I felt supreme peace and bliss of an otherworldly magnitude", etc. Nibbana is, by it's nature, nearly impossible to describe and conceptualize. Like a black hole, it is only discernable to the normal mind by the things surrounding it.

It may be more useful to learn how to experience it than to wonder too much about it, which may engender expectations and concepts that you'll have to let go of eventually anyways. ;)

AN 9.34, Ven. Sariputta says (in translation) ...

nibanna is bliss

... and that what's blissful about it is that there are no "feeling" i.e. vedana.

The word translated "bliss" is sukha.

The word translated as "joy" is (instead) usually piti and associated with meditation (and impermanent).

OP: I have noticed that it seems Nibbana has been described as "the peaceful".

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.