I've had these about 18 months and I have really mixed feelings about them.  I find them comfortable and they look nice.  BUT, I have to tighten all the screws on these at least once a week if not more with an allen wrench. They do NOT work well on a tile floor where the chair gets moved back and forth over grooves.  Tired of picking up screws off the floor and trying to keep them out of pet and toddlers mouth!!!