Hello,
I don't have the full or queen size Naturepedic, but we do have the crib size one for my two-year-old son. It is not too hard t ALL. If anything, it sags a bit in the middle, but that is probably because my son spends about 20 minutes a day jumping up and down on it when he should be going to sleep. I have laid on it, and it is quite comfortable. I plan t o buy a big one for myself when I get a bit of money.
Hope this helps,
Melissa