My RF1200 flows a lot more air and is slightly smaller, but the GT-Air has the second visor which is really nice to have especially early and late in the day on clear sunny days.
I have just replaced my GT air with an NXR. Although I really liked the GT air I was not a fan of the drop down visor (helmet expert at dealer says it makes the helmet noisier.) Alas last year it developed an awful lot of wind noise from the top left of the visor, helmet guy at dealer adjusted it twice and improved, but could not cure it. As it was 5 years old, I treated myself. The NXR is lighter and supposedly quiter, not had a chance to use it yet.
Have had my Shoei NXR since Nov 2014 as you couldn't get the GT-Air with an Iridium Visor at the time and it's been the best helmet I've owned, light and comfortable on tour with better ventilation than the XR1100 it replaced.