Getting back on topic and back to the OP. The sspx/resistance is superior to sedevacantism because it was headed by two holy bishops gathered together. The key words being two, holy, and gathered together. Recall the words of the Lord - "where two or more gather in my name, there I am in the midst of them".
The same cannot be said about the sedevacant movement. In fact, it is ironic, because it is pretty much the polar opposite. You had two bishops alright. But, they were not holy, and they were not gathered together(of secondary importance). You had the scandalous antipope bishop francis schuckardt of the cmri, and +Thuc who pretty much gave birth to everything else. Compare and contrast. +schuckardt became a filthy rich type bishop who came from schismatic excommunicated old catholic lines and ultimately became an antipope. And, the previously filthy rich +thuc became an impoverished puppet of two gathered together laymen(hiller/heller) calling the shots. It is the opposite of the will of Christ.
+Thuc ordained and consecrated more unqualified and non catholic men than he did catholic men(if you want to call them that). +Schuckardt was a druggy who sɛҳuąƖly abused his seminarians. +Thuc flip flopped between vacantism and the conciliar religion. And, he too even created an antipope. So, both camps of vacantism gave birth to antipopes.
+Thuc pre v2 seemed more interested in being a wealthy businessman than a bishop. +thuc apologists shed crocodile tears for the fact that +Thuc had no money post V2, and that he had no other choice but to flip flip/simulate the new mass to survive, and/or bow down to the two laymen running his life. He was not a holy bishop. The two are shameful.
+Lefebvre and +Castro mayer were holy men who kept with tradition, and that is where the church is. +Williamson and company are keeping with the position of those two. And, it goes to show, God does not leave us orphans.