I recently replaced my old Vittoria Randonneurs with a set of Specialized All Condition Armadillo Elites, and the Specialized tires are noticeably faster. Not 10~15%, but I have gained about 1.5km/h on my average speed since replacing the tires, which is about a 6% increase for me.

They're supposed to be pretty good at preventing flats, too, but I can't really speak to that yet - I've only got about 375km on them so far, so not enough time to comment on their puncture resistance.