I just watched the first episode of Inuyasha Final Act. It was weird to switch to subs after watching the series and movies dubbed. Jaken's voice was especially different.
The first episode seemed to be moving fast considering how many episodes there are. I don't know what all the anime is trying to accomplish in the Final Act so maybe it has to be that fast.
The relationships between the characters also seemed odd. I guess I should read up to see if there was a big time skip. But the characters seemed to know things about each other that only the audience knew previously.
The biggest change was Inuyasha taking Kagura's side so quickly.