This arc was about 20-40-40 for me, 20% amazing, 40% subpar, and 40% absolutely terrible (like on a Narudo level). The arc would've been 100% better if Kubo could pace stuff worth a shit.
High points: Szayel vs. Kurotsuchi, Chad chad chad chad chad chad, Arroniero, Dordonii, Nnoitra vs. Kenpachi
Meh points: Grimmjow vs. Ichigo, anything involving Ichigo, Grimmjow's flashback, end of the Nel thing
Shitty points: most of Szayel's fighting, Byakuya vs. La Roux, the latter half of Grimmjow vs. Ichigo, the entire Nel ordeal (sans the end), Hitsugaya's fucking gaidin, and a bunch of other forgettable crap I'm forgetting