If you've made it to this point in the anime, congrats. You're going to be rewarded. Bake and Nise were hit and miss when it came to plot and pacing, but this season perfected those flaws.
I was blown away by how complex and engaging this season's story became. The character development in this season is hardly matched by any anime I've seen. The animation is as wacky and unique as always. The OPs don't disappoint. The end of this season is your reward for sticking it out through the underage fanservice.
My main complaint about this season or the series in general is a lack of screentime for Hitagi Senjougahara. She's painted as a main character since the beginning, but is hardly utilized as a character outside of the episodes dedicated to her arc. It seems like a waste to create such an intricate, unique and unpredictable character just to put her on a shelf over half of the time.