To me brands are less important than the materials in the mattress and the knowledge, service, transparency, and guidance of the people I am buying it from.
There are many parts to value and in the end value is about which mattress is most valuable to you.
First though it’s important to make sure you have all the details of each mattress that you are considering. This includes the density of the base foam.
The next step is to make sure that the mattresses that you are considering are suitable for your needs and preferences. This usually involves some local testing on similar mattresses to get a sense of the general construction and layering you prefer and then more detailed phone conversations with each online merchant (if you are comfortable with any additional risks of an online purchase) to help you “match” the mattresses you have tested to the model that they sell that may be most suitable for you. Your phone calls will also give you a much better sense of who you are dealing with and their level of knowledge, transparency, and service. These phone calls are perhaps the most important part of an online mattress purchase.
Finally … there are many other parts to value besides just the materials in the mattress itself including the knowledge and service of the merchant and the options they offer both before and after a sale. You can read more about some of the more important needs and preferences that may be important in post #46 here.
All of these together will give you what you need to decide on which mattress best matches your own personal “value equation”. What is the best value to you may not be the same as what is the best value for someone else. Each person can have a different set of things that are more or less important to them that are part of a mattress purchase.
There is a list in post #12 here of some of the better online memory foam sources I’m aware of (although of course it’s nowhere near a complete list). These are my “value” reference points.
SleepEz is one of the members of this site which means that I believe they are among the best quality, value, and service in the country. They sell mostly latex mattresses but also have the option of using memory foam for the top layer of their latex component mattresses. They use 5.5 lb Sensus which is made by Foamex/FXI. The standard memory foam/polyfoam mattress they list is the only “traditional” memory foam option they offer so they don’t have as much selection in the typical memory foam category but if you feel this is suitable for your needs and preferences it would certainly make a good value choice.
My Luxury Mattress has also impressed me with their knowledge, service, transparency, and value when I have talked with them which is why they are also on the list. They offer more memory foam choices which may be important in helping you decide which memory foam mattress may best match your specific needs and preferences.
AmeriSleep is a sister company to AstraBeds and SimplyRest. Their memory foam mattresses are made by Anatomic Global which is owned by Foamex/FXI (the customer service rep didn’t know this when I last talked with them). I have had mixed experiences with them (as a group not just with Amerisleep) when I talked with them on the phone ranging from one good conversation to several where they were quite aggressive and high pressure and misinformed about their products. They are basically a marketing company and not what I would consider “mattress people”.
Once you have reached the point where you have eliminated the worst choices and are choosing between “good and good” (and in terms of the mattresses themselves there are no “bad” choices on your list) … then your final choices are more about which is “best for you”. This would take into account all the many parts of a mattress purchase (connected with the mattress and the merchant) to help you decide which one best fits your personal value equation. A big part of that for me would be the knowledge and service of the people I was talking to and my confidence that a mattress and merchant I was considering buying from (especially online) was suitable for my own unique needs and preferences based on their guidance and on my own experiences with local testing of similar mattresses.
Hope this helps.