Hi Euanne,

The difference between the two is subtle but important.

The 100% is the highest quality latex you can buy whereas the 80% is still high quality but at a slightly lower price point due to the blend.

The difference in feel will be minimal, but the longevity maybe slightly higher in the 100% natural.

To give an idea of comparison most shop bought latex is either 100% synthetic or 20% Natural / 80% synthetic.

I hope that helps make your decision easier!

Kind Regards Gary