have used this chair daily since arrival. love the adjustable arm. they do not lock but stay in place well.  the tilt function after 2 weeks needs tightening but is nice to be able to stretch in place.  the width of the seat is wide enough for my hips with the arms down as a plus-sized user. the back is just mesh so if you want a lot of firmer back support I would suggest a lumbar add-on.