I think that if a motherboard is going to advertize (brag) about all the extras they have, then those extras should at least be better than something that can be bought years in the past. Just my 2 cents worth.
I really like the mb, and am looking forward to using some of its features, but it does bother me that they all advertize their on-board hardware like it's something special. I mean, they could just say something like, "comes with basic sound, graphics, and network capability." But I guess that's what they are saying when they say Realtek. Basic.
Yup, it's probably got a difference in CPU usage but with the power of CPUs these days you could be looking at the difference between 1.0% and 1.1%.
The Intel NICs typically have some nice interrupt moderation techniques that strike a good balance between low latency and low interrupt load. It might make a difference if you have some real time constraints in your system, maybe pro audio stuff would show it.