One of the differences I see is in the way the two groups view justification applied to believers. Rome uses the word "infused" to describe Christ's righteousness applied to believers, while the Scripture (and protestantism) uses the word "imputed" to describe it. Huge difference here!

Imputation means that Christ's righteousness is bestowed in a forensic sense; that is declared or pronounced "NOT GUILTY" in the court of heaven because Christ's righteousness is credited to the believer's account by faith rather than works. That righteousness is demonstrated rather than "accumulated" by the believer's good works. The Scriptures speak of three imputations:

Adam's guilt imputed to all his descendants, or what we call Original Sin and human depravity;

Our sin imputed to Christ on the cross and paid for by His blood, fully satisfying God's justice for our sin, and

Christ's righteousness imputed to believers from before the foundation of the world. Christ's work in life, death, and resurrection having fully accomplished the total redemption of the elect.

By using the word "infused," Rome mixes justification with sanctification and removes the forensic sense in which Scripture defines justification by faith.

-Robin