A-1 is really good. They did Anohana (great anime, you will cry your eyeballs out for sure)
But ufotable is the best in my eyes. That's the studio animating Fate/Stay Night - UBW.
Ufotable is good too. But A1 who did UtaPri, Black Butler, SAO II, Persona and Shigatsu wa Kimi no Uso has the best visuals for me.
Naruto lucked out on getting Studio Pierrot--a animation team notorious for fanservice who liked exploiting characters' popularity and were unfortunately huge naruhina fans. I bet if another studio animated Naruto the sh*tty ending would've turned out differently (because they would've worked on getting the heroine Sakura popular and not influenced Kishimoto on canonizing a couple that came from their bias for a character)
Those big 3 (OP, Bleach, Naruto) are know for their massive fillers. But so far Naruto us the only one that I see that is biased on pairings and characters. And they are also known for bad animation too. Characters are getting uglier in each episode.