Came across this product that states it’s a member of Canada Green Building Council. Here is a link- http://concreteinsulationsystem.com/warm-floor/ Seems to have everything I was looking for in a subfloor. A few things I like about it:

Supports loads up to 4000lbs
Is made of high density eps
R value of 3.5
Green
less than 1/2 inch thick
Is a vapor, air, and radon barrier
.95 cents a square foot
You can place finished floor right on top

So anything wrong with this setup? Are claims legitimate, is Canada Green Building Council approval good? Should I use engineered, laminate, or vinyl flooring with this product?