I received these bean bag refills and immediately put them to use filling a chair we've had for over 2 years that had lost its shape and stiffness. The brand of bean bag chair is different from the Posh Creations refill so the actual beads were larger than the original, but they mixed in just fine. Definitely recommend. 
As far as the durability, we'll see how long it takes before these beads get squished and go flat. My guess is it will be a little quicker than the very small original beads simply because they're larger and easier to squish between my fingers.
What I really like it the resealable bag! We knew we didn't need to use and entire refill, so having the zipper to reclose the mesh bag was perfect. The tapered opening was also very helpful for pouring the beads. We ended up using about 1/4 of the beads to fill and reshape our bean chair.