We have an Ecosa matttress love it.

Check out ZZZ Atelier. We were about to buy a Koala but stumbled across some very good reviews for Zzz. We bought one two years ago and are quite happy with it

It's amazing what they can fit into a box these days 😂

I have Koala. Bought it over a year ago. King size. It was meant to be a temporary one until I find the perfect one for us. It was going to guest bedroom after that. It came with yellow discolouring , they explained it was because it sits in plastic bag in hot warehouse. Which seems right. I didn’t try to exchange it.
It is very comfortable. I am in no rush to replace it . It is a little bit like a memory foam. Firm, great support and super comfy. You could be literally jumping on one side and person lying next to you wouldn’t feel it. I am thinking to replace kids mattresses with that ones.