I like the natural look of this rug on my dark wood flooring.   As stated in other reviews, Yes it is knobby, I actually put the underside up, cuz it's less knobby, and the rug is pretty much reversible.  I'll probably flip it over sometime down the road.  Little bit of "fiber" debris but that does not take from the rug at all...  so a couple of months on the floor the rug is fraying on the ends  .Not sure if the warrant covers the fraying..
update.. the rug sheds more than (all) my cats together. Seems because it is jute, (ropelike natural fibers) it will continually shed as long as it is being walked on. Wayfair was great handling problem.