The mat's knobbies on the bottom are just right but it didn't flatten out all the way yet. I have had it a week. Took 2 days just to get the thing to unroll and then I had to point a heater at it. Maybe this summer it will finish flattening....
It is expensive. The cleats aren't nearly big enough for the thickness of carpet this is supposed to work for (3/8") so it slides around. It works otherwise with no cracking yet. It flexes a lot too so you need to rotate the wheels periodically so you don't create divots in the mat. Not sure it's worth the premium given it won't stay put and still flexes a lot.