I recently came across a very interesting line in Alister McGrath's Iustitia Dei: A History of the Christian Doctrine of Justification:
Where Zwingli and Bucer tended to make justification depend upon the believer's regeneration through the renewing work of the Holy Spirit, which enabled him to keep the law and imitate the (external) example of Christ, Calvin understands both justification and sanctification to be the chief beneficia Christi, bestowed simultaneously and inseparably upon the believer as a consequence of his insitio in Christo.McGrath may exaggerate this a little since Calvin would understand union with Christ to be regeneration. Nevertheless, it seems to me that Calvin's move is one step toward Catholic soteriology with one step backward.
First, Calvin properly placed soteriology in the context of the believer's union with Christ. This mystical union is what leads to the reception of the "benefits of Christ", that is to say, justification and sanctification. This ontological model is "more Catholic" in that it makes the forensic transfer of benificia dependent on a real union with Christ.
At the same time, however, Calvin distances himself from Catholic soteriology in two ways. First, he maintains that justification and sanctification (while received together) are absolutely distinct. Second, and most importantly, Calvin maintains that the benificia Christi ("benefits of Christ") are non in nobis sed in Christo - not in us but in Christ. The shame is that while Calvin taught that the believer enters into a mystical union with Christ that is real and seemingly ontological, he teaches that the benefits of salvation are strictly extrinsic! Unfortunately, Calvin comes close to Catholic soteriology but falls just short of it. Calvin breaks with the nominalist model and moves toward a realist model, but then retains Luther's extrinsic understanding of iustitia Christi aliena (the alien/extrinsic righteousness of Christ). So Calvin ends up with this: "I am one with Christ, but not one with his righteousness." As a Catholic, I find this conclusion ridiculous. It is simply Calvin's way of puting a band-aid over Luther's initial mistake. It still doesn't heal the problem.