The engines accomplish the same goal in such different ways that it's like comparing apples and oranges. The N54T is exhilarating and can make you feel like you've been literally kicked in the seat of the pants, but the motor doesn't stir my soul the way a wailing S65 does. That being said, I'm not sure how often the upper rev-range in the S65 can be exploited in daily driving vs. the 1M's big fat torque curve.
My sense is that some 1M owners are still a little butt-hurt by the whole it's-not-a-true-M-car thing. And, there's the simple fact that the M3 is still kind of the yardstick that everything else is compared to.