Hi meyerba,
Post #2 here includes more information about what you can look for when you are considering a used mattress. Although it’s more about buying a second hand used mattress, much of the information there would still be relevant.
This topic and this topic about PLB floor samples may also be helpful.
I would ask as well because the PLB foundation isn’t particularly good quality (see post #44 here and the posts it links to).
The “value” of a mattress purchase depends entirely on what you are comparing it to and on how it compares to the other mattresses that you are considering or that are available to you. There is also more about the most important parts of the value of a mattress purchase in post #13 here.
If you are looking at the Vitality for $799 then it is a significant discount compared to their MAP pricing (minimum advertised pricing) but their MAP pricing is on the high side so the amount of a discount that you receive over a retail price that many people wouldn’t or don’t pay anyway isn’t nearly as relevant as how a mattress compares to other similar mattresses based on the parts of your personal value equation that are most important to you.
Having said that … all the materials are good quality and there are no weak links in the mattress so if you are comfortable with the idea that there have been many people testing the mattress you are buying and some of the additional uncertainty that goes with buying a floor model and the mattress is in good condition, is a good match for you in terms of PPP, and you are also comfortable with the lack of options you would have after a purchase if your sleeping experience indicates that it isn’t as good a “match” for you as you hoped for or there is a defect in the mattress … then I think it would certainly be a good value purchase for you (regardless of whether it would be good value for someone else that has different criteria or that may be comparing it to different mattresses).
Phoenix