I think the difference between your parish priest and the priest from the FSSP is that the FSSP can only use the Roman Missal of 1962 and the Rituale Romanum that was in print during 1962. I believe this is part of the Ecclesia Dei indult. In other words you will not see the FSSP priest assisting (concelebrating) at a Novus Ordo Mass or distributing Holy Communion at a Novus Ordo Mass.
Also the FSSP does not take vows. In addition, if your parish priest is a Diocesean or “secular priest” he does not take vows either. He simply makes a promise of celibacy, and obedience to the Bishop.
Priest of religious orders, such as the Franciscans, and those close to my heart, the “Missionaries of the Sacred Hearts” (by the way their founder is going to be cannoized I hear), take vows of “Poverty, Chastity and Obedience”.