Just finished the entire series. The writing is very good. And I loved the story. However, animation is a disappointment I will admit. Whenever I saw a character with a brand new character design, I was like Yup, this is another main character which kinda ruined the emersion for me. There was this one animation mistake where Po's head snaped back in place. Lots of it were copy and pasted. The characters, non main characters walking, the background. The scenery wasn't that good either. They even reused previous side characters as background where they were in a completely separate location. I wish they took this opportunity to expand on the world of KUNG FU PANDA a bit more. Seeing the universe of KFP outside of China was really cool, wish they did more with it. One thing that happened in the story did not make any sense to me but I won't mention it because its a spoiler but it is not part of a big plot or anything.
I overall love the series but I got to admit, the animation wasn't that great. Definitely not boring by any standards though. I recommend.