Great weight and durabilitiy -- slips a little with chair action but protects carpet below. Simple tug once in a while brings it back into position I prefer.
I haven't had this mat for very long. About a month into using it I noticed that the plastic mat had formed indents where the casters of my chair usually sit. The casters get caught up in the indents and it has become difficult to move my chair to other parts of the mat. I'm not impressed with the mat. Oh and I weigh only 125 lbs and I have an average size office chair so I don't think I caused this problem.