I personally think Amity making the balloon the fly off the flowers was a smart move, it was as if Luz was literally letting go of her guilt of not being with her mother, having it fly away.
For example, the Manga has Futaba getting sick and Takeda getting sick as being two completely separate incidents while in the Manga is it also implied that Takeda gotten sick while trying to nurse Futaba back to health.
Yuuta isn't present during the Valentine Chocolate Arc or the New Year Arc
The New Year Arc was in the second to last Ep of the series while in the manga, it happens way before the Valentine Arc.
I personally like some of the deviations, the comedy hits better (Kazama heartbroken because he thought Yuuta was Sakura's bf was funny as f$%#) and Takeda and Futuba exchanging presents is better than Futuba just getting one.
What do you guys think?