He Lives Blog thinks that he has his finger on the pulse of what bugs Catholics and Protestants respectively in apologetics.

The insight I have had (again, it is most likely a belated epiphany) has to do with what bugs one group about the other. I assumed that each had different side of the same coin as their most important point of departure. I am now reasonably convinced that each is most concerned about different sides of different coins. Protestants (well, at least this Protestant) are (rightly, honorably, and justifiably) still most concerned with Rome’s denial of Justification by Faith Alone (sola fide) and the unconscionable anathemas placed on the Reformers at the Council of Trent. The thing that bugs Catholics (at least those I’ve been talking to) most is the Protestant proclamation of Scripture Alone (sola scriptura) and the fact that is linked to the dreaded Private Interpretation.

Sola fide and sola scriptura are both important aspects of the Reformation, and are quite related. Nevertheless, the button to push for a Protestant tends to be sola fide, and for a Catholic, it is sola scriptura (and Private Interpretation).