Few factors:
1. Totsuuka is useless against Sasukes Susanoo, it would have to pierce it in order to seal it.
2. Sasukes Susanoo changed, I dont think its only for show, its practically certain that it is boosted as well.
3. 4th Mangekyou technique. Considering its EMS technique it should be pretty darn powerful, at least on Susanoo level if you ask me.
4. Using Mangekyou techniques takes less strain on Sasuke, than Itachi.
All in all, Sasuke has clear upper hand at least on paper.
1. Totsuuka is useless against Sasukes Susanoo, it would have to pierce it in order to seal it.
2. Sasukes Susanoo changed, I dont think its only for show, its practically certain that it is boosted as well.
3. 4th Mangekyou technique. Considering its EMS technique it should be pretty darn powerful, at least on Susanoo level if you ask me.
4. Using Mangekyou techniques takes less strain on Sasuke, than Itachi.
All in all, Sasuke has clear upper hand at least on paper.