This review contains minor spoilers.
The story was great. I watched the movie last year and I actually disliked it until I read the manga which completely changed my mind. I can't recall if the movie had the same ending as the manga but the manga definitely had more content than the movie.
The art was incredibly beautiful. I literally stared at some of the bigger pictures for minutes because it was so good. The character designs were really nice and I liked the way Midori Motohashi drew them when they were blushing and how she sometimes drew these big pictures of the park.
The garden of words also uses small subtext that's fairly easy to understand. Such as how Yukino recognized the schools emblem on Takao's shirt. But the most beautiful use of subtext was how shoes and walking were used in the story. Yukino lost the ability to walk properly which basically means that she can't move on from the past because of fear of the things that hurt her before. Takao intends to make shoes that will make her want to walk again and this means that Takao pretty much just wants to help her with her worries and help her move forward.
So like I said it uses subtext but not to the point where you have to sit yourself down after reading it and think "what the hell did I just read?" which I think is a really good thing.
The ending was really nice and showed that even though Takao might believe that he's too young he still managed to help Yukino and made her able to "walk to the ends of the earth."
So overall I really enjoyed the garden of words.