I bought the soft model, which had the least filling, compared to the medium and firm ones.
The soft one is supposed to be suitable for sleeping on your stomach, the medium one for sleeping on your back, and the firm one for sleeping on your side.
I assure you that I have tried the soft one for all three sleeping positions.
It is not comfortable for any of them!
Sleeping on your stomach feels suffocating, sleeping on your back hurts your neck, and sleeping on your side causes your head to sink in.
(I don't know if the other options would help, even for side sleeping, but the firm one was like cement, it wouldn't budge at all. I don't think they would be any better.)
It doesn't provide any quality support for the head.
The material is also synthetic, so the side you lie on gets hot. Not a pleasant feeling at all.
Unfortunately, it was a failed choice. The pillow is not worth buying. It creates problems instead of solving them. Of course, I don't know if similarly priced silicone pillows would have the same issues.
The only use I found for it, after trying it out, is as a back pillow. But since it is advertised as a pillow for all sleeping positions and doesn't serve the purpose it claims to, I attach a negative review to it.

Comfortable soft and low pillow with good quality cotton fabric. Particularly good for those who sleep on their stomach.

At first, it seems impressive, but after two or three nights, it's not fluffy anymore, waste of money...it's suitable for cuddling, but not at all for the head!