Just to get everyone up to speed, the Conti Road Attack is their Sport/Touring tire. The Sport Attack is their sport tire.
On FRONT there isn't much difference between the SPORT Attack and the Pilot Power as far as grip and ride quality. The Conti may go a bit longer, but that's hard to say for sure. I don't like the Road Attack front.
Rears:I've changed and worn about 6 of each, Continental Road Attack and Power Pilot. (counting the 929) On the 919, I get about 4200 miles out of a ROAD Attack rear. I get about 3200 miles out of a Pilot Power rear. I did a track day on the Road Attack. It was a fairly hot Sept day. Knees, pegs, toe sliders were all on the floor. Bike did nothing stupid. I think the Road Attack rear is a good match to the weight and power characteristics of the 919.
Since I change my own, I will add that the Conti Road Att is aprox 3 lbs heavier than a Pilot Power. You get more rubber with the Conti, maybe that's where the extra 3 lbs come from. Michelins are easier to change. They're more plyable, spoon on with less force.
I have my first Sport Attack rear on the 919 right now. It has only 700 miles on it and is still nice and round, and still looks new. Time will tell...