Hi Co-Hoya,
I think LEW’s comments are a close reflection of what I would say as well.
The quality/value of a mattress depends entirely on the construction and quality of the materials inside it and since they are completely open about what is in their mattress, any feedback about the same materials used by any manufacturer would apply to those same materials in a mattress made by any manufacturer.
Of course each manufacturer may offer different levels of knowledge, service, and experience and make different options available to their customers so knowing more about them and what they offer can also make a big difference in each person’s personal value equation.
As LEW also mentioned … I would also place a premium on the lower risk and other benefits that can go with dealing with a local manufacturer or retailer vs online and as an arbitrary number I usually suggest a local premium in the range of 20 - 25% or so would be “roughly equivalent value” but of course each person may have their own number and risk tolerance.
In my brief interactions with foamsource (a couple of phone calls) I have found them to be knowledgeable and transparent and they have been in business for over 25 years so I personally wouldn’t have any issue dealing with them. I would measure the quality and value of their mattresses in the same way I would any other based on the materials that are in them, the benefits of dealing with that particular merchant, and on the other parts of your own personal value equation that are most important to you.
Phoenix