I purchased this chair for 285 lb, tall person and he uses it for work.  It is comfortable throughout entire work day.  The seat width is wide but the seat depth is also larger so it doesn't leave a tall persons knees hanging so far out from the chair edge.  So far there hasn't been an issue with the chair sinking down while sitting in it.  We've had it for about 3 weeks and I am happy with my choice.