My cat's opinion was "Meh," mostly because the dark brown outer layer is not firmly attached to the inner beige layer. So the inner beige layer fully collapses and forms a wall, of sorts. Because of this, my cat would not really use this sack, even though she has a "burrowing" personality. If I quilted this sack with lots and lots of quilting knots, it might be usable. The sack materials are high quality, but the design is flawed.