750g in 15" small translates up to about 885g at 20.5" xl. They have a 213mm steerer, allowing for a xt headset at 33mm stack.
The non lightweight version at 20.5" for comparison is about 1060g
The lighter version is a better ride as a bit more compliant....probably due to the internal butting and thinner tubing. But the heavier version is far better is you want to add luggage!