This pillow is very firm. I prefer a softer pillow, but if I'm sitting up in bed, this is definitely going to be ideal for that use.
My husband used this to take a nap on when he was sick and needed to stay elevated to breathe better. He liked it for that, but for an everyday sleeping pillow, I think it would take some getting used to, as it is too high for a person's head/neck. I normally have my pillow placed behind my neck and head. This pillow, I would have to have my shoulders on, so my head wouldn't be pushed forward.
I believe the core of this is a tightly wrapped filling, surrounded by looser fill.
Again I think it's a great "propping" pillow, like if you're leaning against a couch playing a game on the floor or watching a movie. Good for elevation. Great for elderly who need propped up behind their back. Maybe even good for hospital patients who are confined to their bed.
But no, not for me for sleeping...it doesn't have any give in it...maybe it'll get worn down over time.
This pillow is designed to not go flat, hence the name. So I'm not knocking it for being what it's designed to be. Just saying how I feel about it.
The pictures don't reflect how puffy and full this pillow is. I'm not sure why, but keep in mind, it's fuller in person, than in my pictures.