Hi Mercador,
The “value” of a mattress purchase is always relative to the other mattresses you are comparing it to or that are available to you in terms of suitability and PPP (Posture and alignment, Pressure relief, and Personal preferences), the durability of the materials inside it, and all the other parts of your personal value equation that are most important to you. A mattress that would be good value for one person or in one area may not be good value for another person or in a different area where there are different mattresses available.
I would be very cautious about using reviews (either positive or negative) as a reliable source of information about either the suitability or the durability of a mattress and in many cases they can be more misleading than helpful because a mattress that would be a good choice for one person may be completely unsuitable for someone else to sleep on (see post #13 here).
There is more about the most important parts of the “value” of a mattress purchase in post #13 here that can help you make more meaningful comparisons between mattresses.
There is also more information about the Dormeo Octaspring mattresses in post #2 here that may be helpful but I would make sure you can confirm the thickness and density of all the layers in the mattress (see this article) before considering it.
Just in case you haven’t read it yet … I would make sure that you’ve read the mattress shopping tutorial here which includes all the basic information, steps, and guidelines that can help you make the best possible choice … and know how and why to avoid the worst ones.
If you let me know your city or zip code I’d also be happy to let you know about any of the better options or possibilities I’m aware of in your area as well.
Phoenix