It’s really soft, comfy, and so far no dipping! I did notice the king wasn’t available a while ago (maybe I recommended too hard? LOL), but I’m going to pass along the link which will at least have the specs of the ones we purchased.
We got the 10” Zinus king size and the 6” zinus twin for the kids. (I’d bump theirs up to 8” if I could do it again.)