With a false bishop appointed for themselves by heretics, they dare even to set sail and carry letters from schismatics and blasphemers to the chair of Peter and to the principal Church [at Rome], in which sacerdotal unity has its source; nor did they take thought that these are Romans, whose faith was praised by the preaching Apostle, and among whom it is not possible for perfidy to have entrance." (Cyprian, Letter 59 (55), 14 to Cornelius of Rome, c. AD 252)
"[After quoting Matthew 16:18f; John 21:15ff]...On him [Peter] He builds the Church, and to him He gives the command to feed the sheep; and although He assigned a like power to all the Apostles, yet he founded a single Chair, and He established by His own authority a source and an intrinsic reason for that unity. Indeed, the others were that also which Peter was; but a primacy is given to Peter, whereby it is made clear that there is but one Church and one Chair. So too, all are shepherds, and the flock is shown to be one, fed by all the Apostles in single-minded accord. If someone does not hold fast to this unity of Peter, can he imagine that he still holds the faith? If he desert the chair of Peter upon whom the Church was built, can he still be confident that he is in the Church?" (Cyprian, The Unity of the Catholic Church [first edition] 4, c. AD 251)
I have recently been either progressing or regressing - depending on where you stand - towards Roman Catholicism or away from Protestantism. Ironically reading R.C. Sproul's fair explanation of Justification according to Rome, I have realized that I agree with it for the most part. (every once in a while the sudden urge to shout Sola Fide nearly overwhelms me, but I'm living with it now)
My point basically is this Reformed/Calvinistic Protestantism offers a biblically coherent model for Justification. Catholicism offers a biblically (and traditionally) coherent model of Justification/Sanctification. Here is the difference that makes EVERYTHING when deciding on the church for me: which is the 'real' church. Obviously both sides have great manifestations of Christ such as Thomas Aquinas and John Wesley, obviously God works in both. But in the form of a question one Orthodox apologist posed to me: Which is the church that the apostles would recognize? Which is the faith for which the martyrs died? Which has protected the unity of the church and can without equivocation be called "One Holy Catholic and Apostolic". The clear answer to me is Catholicism.
While many scholars (even Catholics like Hans Kung) will show that there have been many problems in the church, there is a clear winner I think. It's not so much that I love Pope Benedict XVI or I love the Priesthood as much as it is that I love the Church, and I believe firmly in the unity of the Church, I'm siding with Erasmus here in saying that Reform is needed, but from the inside. And as St. Cyprian shows us above, the communion of Rome is the Ancient Christian church.