Any idea what the maximum height of a person would be to use this?
All these adjustable desks start to have perceptible sway when mostly extended. If this really bothers you, consider mounting your monitors separately.
http://www.ikea.com/gb/en/catalog/products/S49061191/
http://www.ikea.com/us/en/catalog/products/S49022524/
http://www.ikea.com/se/sv/catalog/products/S69022537/
http://www.ikea.com/dk/da/catalog/products/S69022523/
The Swedish and Danish versions have the same product code, but the British one is different, yet I don't see any difference in the description. Maybe it's just the different plug.
Americans also benefit from a warning not to be crushed by their furniture.