Hi coachnoel1,
Welcome to the Mattress Forum! 
The basic answer, from my many conversations with them, is that SleepEZ realizes, as we explain here, that reviews are the least reliable way to pick out a mattress, and reviews or other people’s experiences in general won’t tell you much if anything about the suitability, quality, durability, or “value” of a mattress for any particular person (see post #13 here). They instead focus upon the componentry within their mattresses and using their experience to provide educated advice to their customers. They are one of the oldest latex component companies in North America, and you’d be hard pressed to find one with a better reputation.
They are not reviewed (this is not a mattress review site), but they are one of the few manufacturers who have been extended and have accepted an offer of membership here. See here for more information about the qualities needed to be considered for membership here on the site. I consider the business members here among the best in the industry, and I’m happy that this provides you some reassurance.
They did just go through, and are still going through, a complete web site redesign, and they have indeed changed the format of their Testimonials page. So their explanation to you is accurate.
Yes, they have one of the longest histories in the industry for component-style mattresses.
Whether or not a company is mentioned, or chooses to participate or advertise on any “review” web site, has absolutely no bearing of the quality of product, level of knowledge or service that a business or manufacturer offers.
There are some review sites that amalgamate mattress reviews from all around the internet for example, and then “rate” mattresses (and other products) based on these amalgamated reviews And while most reviewers are certainly well meaning … because most reviews aren’t relevant to anyone but the reviewer and can be “influenced” so easily and in so many ways … for the most part (with only few exceptions) mattress reviews are a classic example of garbage in / garbage out even though the “garbage” may be well meaning and true to the experience of the person writing the review.
I don’t know that you are “missing” anything, but I think that you are placing an emphasis on “reviews” that I advise people to avoid, per the information I linked to above. I’d advise you to focus more upon componentry and follow the guidelines as outlined in the mattress shopping tutorial here, as this will help you make a more objective and informed mattress buying decision.
If you do choose a SleepEZ mattress, they use materials that are durable and of high quality and I wouldn’t hesitate to recommend them for your consideration.
I hope that information helps you out. If not, please feel free to post back with more specific questions and I’ll do my best to answer them for you.
Phoenix