I upgraded to these from my 2009 9Ks. They are lighter, stiffer, more responsive, and more comfortable.
Reebok has improved the fit, both in the boot itself as well as the air bladder. The new hybrid foam/felt tongue is the most comfortable tongue I've used. The 9K was a solid skate, and Reebok has managed to improve every aspect with the 11K.
No word on durability. They've only seen light use due to a lack of ice in my immediate vicinity, but they've performed well thus far.
I have wider feet thanks to some surgeries on both feet, so Reeboks and CCMs are generally my only choices without going custom. I've skated on the last three generations of Reebok boots and this is by far the best.
The price is steep, but I'd pay it again.