Horrible! This is one of the most uncomfortable office chairs I've ever sat in, and the most expensive! The seat feels like it tips forward so I have to engage my legs constantly to keep from leaning forward. After just a few days my back was killing me but I didn't have an alternative chair to use. I've hade the chair about 5 months now and the piston thingy that lowers and raises the chair has stopped working. I raise it all the way and within 10-15 minutes I'm almost to the floor. 
Not impressed in the slightest.