Hi dudeitsmattk,
“Furniture grade” is a generic and non specific term that means that the foam would be suitable for use in furniture cushions and would be relatively durable. It usually refers to polyfoam that is 1.8 lb density or higher. As you can see in the guidelines here … 1.8 lb polyfoam would be a good quality and durable choice in your budget range.
The “value” of a mattress purchase is relative to the other finalists you are comparing it to or what else is available to you either locally or online but there is more about the most important parts of the “value” of a mattress purchase in post #13 here.
In the absence of any other mattresses you are comparing it to though … if you are confident that the mattress is a good match for you in terms of PPP and you are comfortable with the somewhat greater uncertainty that comes with Chinese materials then there are no obvious weak links in the mattress and if it is also a good match for all the other parts of your personal value equation that are important to you (including the price and any options you have after a purchase) then I think it would make a good choice.
Phoenix