Earlier quoted context omitted.
For the Ikea Bekant desk, I'm 6'2" and usually have it near its maximum height. I like things a bit higher (relative to my own height) than most, but I still wouldn't expect it to work for someone over say 6'5". All these adjustable desks start to have perceptible sway when mostly extended. If this really bothers you, consider mounting your monitors separately.
The Bekant's EU version goes 3cm higher than the US version. I'm 6'1" and it's nowhere near maximum. A colleague of mine is 6'4" and doesn't max it out either. Height is between 65 and 125cm for the EU version, versus 56 to 122cm for the US version.
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.