I felt that it wasn't till the Hueco Mundo arc that the quality dropped.
It was strecthed too long, Kudo said himself he made it longer cause of the immense fan <3 response in Japan.
Fake Karakura Town arc was great to me, minus Gin's unclear and short flaskbacks.
The Lost Substitute Shinigami arc......was a mess I don't need to go into.
So far this final arc has some really good signs, but I agree with Khan and hope it doesn't become a "Let's kill everyone" mode unless it advances the plot.
Still my fav of the BIG 3. Not to say I don't like OP, cause I read it every week and it does have it's amazing momments (and the humor is always top notch), it's just I don't see me wanting to re-read it again hence why it's the only 1 of the big 3 I don't buy the translated manga.
