Hi tsunamis,
There is no long term experience on any of their mattresses because they have only been selling them for a little over 3 years (and many of them for less than that) and this isn’t nearly long enough to assess the durability of any good quality mattress although the materials they are using have a much longer track record of being used in mattresses that are made by many manufacturers for many years.
I would be very cautious about using mattress reviews (positive or negative) about either the suitability of a mattress in terms of PPP (Posture and alignment, Pressure relief, or Personal preferences) or the durability of a mattress as a reliable source of mattress research or information and in many cases they can be much more misleading than helpful (see post #13 here).
A mattress is only as durable as it’s construction and the quality/durability of the materials inside it regardless of the specific mattress or the manufacturer that makes it and there are much more reliable ways to assess the durability of a mattress or know whether it has any weak links in its design than using reviews (see this article and the quality/durability guidelines that it links to). There is also more detailed information about the many variables that can affect the durability and useful life of a mattress relative to different people in post #4 here and the posts it links to.
Phoenix