Owner of this specific (queen size) mattress, I write only to help some in their choice, as it is too early to evaluate the product.
I quickly mention that in the store in the area of Acharnes I found a wide range of mattresses for all tastes, but also a saleswoman willing to help.
From the beginning, I was looking for a quite firm mattress and found this feeling in more than 2-3 mattresses I tried at the exhibition. In fact, one of them was from the company's basic series and more affordable.
My wife and I ended up with the moss because it seemed to give us the stability (firmness) we were looking for, also because it is mainly made of natural materials and because - perhaps due to its height - it gives a sense of luxury as if you had a topper (this last criterion turned out to be wrong).
In practice, the mattress is quite firmer than it seemed to us at the exhibition, to a degree that surprises me that the company classifies it as medium firmness. This is a characteristic that does not "bother" me, but some may be concerned. In reality, the moss might need a topper that would give it the progressiveness it lacks, but on the one hand it is too early to judge and on the other hand it is already too high to add more height.
Finally, I should mention that in the last decade I had a firm mattress (from a very strong brand in the field) which I combined with a latex topper, having a wonderful overall result. In the market research I did now to replace it, I noticed that the -at least external- construction materials are now more cheaply made in all companies. Including greco strom, despite offering a good variety and image in its products, really a pleasant surprise for me, which ultimately made me trust it.
Early conclusion: If I get used to the firmness (probably easy, it's a matter of days) and if it doesn't "sink" in 4 years (probably difficult!), the moss will be a good purchase for me.
Choosing a mattress is a gamble, good luck to everyone...