For many years I offered nothing on "Son of God" as a title of Jesus for these reasons:

• "Son of God" by itself offered little in the way of defining content. As critics are eager to note, it was a title used of humans in the OT (e.g., Is. 62:8), and by pagans of other subjects. That "God" here means YHWH is of some importance, but still does not give us much in the way of defining content. Other titles like "Wisdom" give us a great deal more defining content.
• The use of the term by Jesus is rare -- John is where we find most of these.
• Its application is to the incarnate Jesus -- it is not used of the pre-existent Jesus until perhaps later in the patristic era. There are certain uses in the NT which seem to have it applied to the pre-incarnate Jesus (eg, Heb. 1:1-2, Col. 1:14-17) but I take these as cases of the authors using the title as a prolepsis.

That said, too many critics make the mistake of trying to debunk the importance of "Son of God" as a title while ignoring or giving short shrift to the others. It is not entirely without meaning, especially when paired (as in Paul) with "only begotten". It does signify Jesus' unique status with relation to the Father, but admittedly does require data from the other titles to obtain its full significance. Critics find hollow victory in their efforts to make too little of it.