Herman Bavink’s Reformed Dogmatics contains one of the best treatments of Christology to be found. At one point he includes a helpful discussion of the title "Son of Man."
Here are a few key quotes:
Taking all this [previously discussed exegetical material] into consideration, we realize that with this name Jesus intends to distinguish himself from and position himself above all other humans. The name also undoubtedly implies that he was truly human, akin not only to Israel, but to all humans; yet it simultaneously expresses the fact that he occupies an utterly unique place among all humans.
Bavinck, Reformed Dogmatics, 3:250
It does not follow that the people in general, or that even the disciples, on hearing the name, immediately thought of the Messiah. The opposite is likely the case, because he was never attacked on account of this title. People perhaps understood by it only that he was special, that he was an extraordinary human being, a fact that was immediately substantiated by his words and works. But for that very reason this name afforded Jesus an opportunity to cut off in advance all misunderstanding about his person and work, and to gradually inject into that name and unite with it the peculiar meaning of the messiahship that, in accordance with the Scriptures, was inherent in it to his mind.
Bavinck, Reformed Dogmatics, 3:250
So then Jesus chose this name for himself to make known: (1) that he was not just the Son of David and King of Israel but the Son of Man, connected with all humans and giving his life as a ransom for many; (2) that he nonetheless occupied an utterly unique place among all humans, because he had descended from above, from heaven, lived in constant communion with the Father during his stay on earth, and had power to forgive sins, to bestow eternal life, to distribute to his own all the goods of the kingdom; (3) that he could not grasp this power violence as the Jews expected their Messiah to do, but that as the Servant of the Lord, he had to suffer and die for his people; and (4) that precisely by taking this road he would attain to the glory of the resurrection and the ascension, the elevation to God’s right hand, and the coming again for judgment."
Bavinck, Reformed Dogmatics, 3:250f.