Hey azaz123,
Thanks for the information…because each person is different in terms of their physiology, weight distribution, and body shape as well as the positions they sleep in, their individual preferences, and the specifics of any back issues they may experience, there is no such thing as a mattress that is “better for backs” in general because a mattress that is good for one person’s back (or back issues) may be completely unsuitable for someone else to sleep on … even if their body type, sleeping positions, or back issues appear to be fairly similar. There is only a mattress that keeps you in good alignment which would be best for YOUR back.
In general … what you would be looking for is a mattress with firm enough deep support and then comfort layers that are “just enough” in terms of thickness and softness to “fill in” and support the more recessed parts of your sleeping profile and relieve pressure in your most pressure prone sleeping position (usually side sleeping for those who sleep in this position) so that there is less risk to alignment in your other sleeping positions. This is another reason why reading “reviews” sometimes has the opposite effect of helping one choose what’s best.
There is also more about primary or “deep” support and secondary or “surface” support and their relationship to firmness and pressure relief and the “roles” of different layers in a mattress in post #2 here and in post #4 here that may also be helpful in clarifying the difference between “support” and “pressure relief” and “feel” although this may be more than you really need to know to choose a mattress that is a good “match” for you in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences).
If you have the time, and want to read…two of the more important links in the mattress tutorial that I would especially make sure you’ve read are post #2 here which has more about the different ways to buy a suitable mattress that is the best “match” in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) that can help you assess and minimize the risks of making a choice that doesn’t turn out as well as you hoped for that are involved in each of them and post #13 here which has more about the most important parts of the “value” of a mattress purchase which can help you make more meaningful comparisons between mattresses in terms of suitability, durability, and value.
Hope this helps!
Sensei