I think IB is brilliant in some ways, but not as good as Pulp Fiction or Resevoir Dogs.
In his earlier works Tarrantino did a better job of amazing you with how he was able to weave different storylines together and make them all fit in a way you didn't see coming. Second was the dialogue, then his characters overall.
IB had typical Tarrantino characters and dialogue but there was no sense of holy shit he managed to bring all of it together in the end.
On the other hand I enjoy this one on another level. I think it is cathartic in it's own ways, visting horrors on the Nazi's who were responsible for horrors themselves. Tarrantino keeps this very graphic, which I think is the way it should be done. The IB's are obviously psycho-paths, and Tarrantino shows this side of the characters as well (I'd give some examples, but the one that really stands out to me would be a spoiler.).
I also thought that it was some of the best cinematography I've seen in his films.
All in all good, but no Pulp Fiction.