Logic has realtime mixdown function, it´s in the manual how to do mixdown. kinda´ easy. Only problem is once you use more layers, where the project file is vulnerable to overloads, you wouldn´t be able to mixdown, since it´s realtime, it dropouts during mixdown. Unlike Sonar, which even when dropout during playback, still can mixdown.
Moreover, Logic´s realtime mixdown is slow since it has to play the whole song to mixdown.