I got it just yesterday (Monster Ultimate Tall). As mentioned above, finding it good enough (coming from a generic office chair).
• Wheel assembly is metal and solid/ heavy. Smooth rolling.
• Seat is well cushioned
• Seat back is large. Ergonmically for the working position, I do not find as much support as I expected. If I lean back, the seat back is comfortable. Lack of ventilation - I think it is more of an issue for the seat bottom than the back.
• Seat is wide enough to sit cross legged, so is comfortable for home use.
• Arm rests and seat back tilt mechanism are okayish.
• Is it worth the 18k? Not sure of the alternatives, so went with it.
Was considering one of the Featherlite (liberate or the higher version) but made an impulse purchase.