Salvation. I believe fully that the Catholic Church has the fullness of Truth. I posted about Father Matt Kennedy's posts on Sola Scriptura because I found their arguments interesting.
I think the evidence of the shortcomings of Sola Scriptura can be seen in the multitude of Protestant denominations. Also the Protestant apologetic for Sola Scriptura varies. Some teach that it necessarily excludes creeds and the teaching of any church councils. While others such as Calvinists do embrace the creeds and the teachings of some Church councils.
During this time when we contemplate our Lord's Passion and His glorious resurrection I prefer to remember what we hold in common we our Protestant brothers and sisters. That we love and serve Christ with all our hearts, minds, will and soul should unite us over our theological differences. Jesus is Lord.
When you take into account that it was the Calvinists and Reformers who "defended" Sola Scriptura (i.e. they embraced the creeds and teaching of some Church councils as a "lesser" authority), it makes sorting out the sometimes conflicting apologetics a bit easier. Those who came later, i.e. those who believe it excludes the creeds and councils equally reject the Calvinist/Reformed creeds and councils, too. Their Sola is more of a Solo.