I have an older "B" that I've had for about 3 months. As a "work" chair, sitting with good posture, I think it's unbeatable. But as a slouch-with-feet-up-on-desk chair, which is frequently my posture at my "work" desk at home, I find it to be less ideal than some of my previous crappy chairs. I have lumbar support so no issues there - I wouldn't want to use this chair without it. I've also added a headrest from Atlas and can recommend it wholeheartedly, despite its hefty price tag.