Hi Loiroi,
Each person is unique and a mattress that is “perfect” for one person may be completely unsuitable for someone else to sleep on. Having said that … medium would probably cover the single largest part of the bell curve that would be suitable for more people than the other two firmness levels.
The Alexander Signature Select is a memory foam mattress (memory foam over a polyfoam support core) and the Alexander Hybrid Signature Select is a pocket coil/memory foam (memory foam over a pocket coil) so they are in completely different mattress categories (see this article) and would have a different feel. They also have differences in the comfort layers (the specifics of the memory foam in all of their mattresses and firmness levels is listed on their site).
You can see my comments about the Consumer Reports mattress ratings and recommendations in post #2 here and in this topic. While they may be a good source of information about more “objective” purchases … as you can see I would consider them to be an unreliable source of information or guidance about purchasing a mattress and they are somewhat nonsensical and meaningless. My thoughts are also shared by most of the more knowledgeable people in the industry (see post #5 here for an example).
You can see the better options or possibilities I’m aware of in the NYC area in post #2 here (including Nest Bedding’s newest store).
@ zexpress
Just for reference … Nest Bedding’s mattresses are made by several different manufacturers.
While some information can legitimately be considered to be proprietary to a manufacturer … there are many manufacturers that claim that the information you would need to make an informed choice is also somehow “proprietary” but I certainly wouldn’t agree. You can read a little more about “so called” proprietary materials and using this as a justification for not disclosing what I would consider to be essential information here and here and here.
Another manufacturer would need much more information than just knowing the quality/density of the materials in a mattress be able to duplicate it. If all they disclosed is the type and quality/density of the materials in his mattresses that can affect durability they still wouldn’t need to disclose the “comfort specs” or other information that would be the biggest part of how a mattress feels. Any manufacturer that was truly interested in “duplicating” one of their mattresses also would have no trouble buying one if they wanted to and “reverse engineering” it anyway.
I would avoid any manufacturer or retailer that either can’t or won’t provide you with the “quality specs” you need to make an informed choice and confirm the quality and durability of the materials and the mattress “as a whole” because this type of “blind” purchase would be much too risky and there are many manufacturers to choose from that will provide you will all the information you need to make an informed choice.
Phoenix