Hi StevieB,
You can see my comments about the Joyful in post #9 here.
I personally wouldn’t consider it … or any mattress where information about the layers of the mattress or the quality of the materials that are used was not available. It is just not worth the risk of buying a mattress that uses low density/durability foams (their high density foam ranges from 1.35 lb to 1.8 lbs with the lower densities usually being used in the comfort layers).
This is the reason for the first guideline in this article (avoid the major brands). I also wouldn’t walk through the front door of most of the larger chains. Both of these significantly increase the odds of ending up with a low quality/value mattress.
Some of the better quality/value options or possibilities in the Greater Toronto area are listed in post #1 here.
In the sub $500 range for a full size set you are not looking at good quality anyway but I would still be looking for the “best possible” quality and value in any price range which you will normally find from smaller local manufacturers that sell either factory direct or though better sleep shops.
Phoenix