When you say "smooth as hell" I am pretty sure we all know you are exaggerating. I am pretty sure the differences the minimal difference in overall diameter would be almost unnoticeable .... based on the fact that I don't feel a "smooth as hell" sensation when I ride my 27"-equipped '84 Cannondale versus any of my 700c bikes.
A 29" MTB set-up is Significantly greater in diameter than a 26" set-up---so there is a significant increase in roll-over capability, which matters on very uneven surfaces. On pavement, I sincerely doubt there would be a any noticeable difference between a 27" and a 700c running equivalent tires---based on actual experiments.
Others' mileage will vary.