There are very few words that can describe this manga and even more so most of the work done by Seo Kouji. Kimi No Iru machi is a masterpiece that really does a fantastic job at tugging at the emotions of the reader emphasized by excellent artwork and a dynamic and hard to stop reading storyline. However this is not the first time Kouji has created such a masterpiece as his work on Suzuka was incredible as well.

Lets talk about the characters for a little bit. I will start with what was probably what held this manga from getting a perfect score on my personal list (word processing not on MAL) which was Haruto Kirishima. Haruto all in all was an excellent character but being a large Suzuka fan previously to reading this manga, I had to say there were points in the story where he was a stronger protagonist. There were just moments where he did not act as strongly as Yamato did in the Suzuka manga (although he had to because suzuka was a total ass sometimes). His caring and learning throughout the manga however was extremely well portrayed throughout.
The second character I want to speak to was Akari because to be honest she was probably one of my favourite characters. Akari was what everyone always wishes for in a childhood friend in being caring, compassionate and funny at times. Her unrequited love for haruto really was a point which I believed could have been emphasized a little more throughout the plot and her exit from the series was lackluster and disappointing in a lot of ways. I really think an arc in this series with her and Haruto dating would have been interesting but shes also my favorite so of course I'll cheer for her.
Finally any discussion of this manga cannot end without speaking to what was the most important character although not the protagonist being Eba. Eba is a lot of ways a character that you hate to love but also one that you love to hate at times. In the earlier chapters there were times you really hated her guts, I mean like you wanna slap her across the face but there are so many more times where the emotion in her character really overcomes you and makes you feel feeble and in love (in a good way). Eba is by far the greatest character in this series, her artwork was amazing, she was very pretty (but not too pretty) and soo soo lovable many times. Her interactions with other characters be it Haruto or, Rin or even Kyousuke are spectacular and awe inspiring throughout the series.

The artwork in general in this series was fantastic, I cannot say it is the best artwork by any mangaka ever but it is definitely in the upper echelons of the minor amount of series' ive read to date (about 130). The mangaka is also one of the best in the business, I mean the story, the art, the dialogue is all top notch and even touching at moments. This is the 3rd manga i have ever read which really pulled at my heartstrings and made me really come out with emotion (suzuka also by Seo Kouji was the 1st and I rather not disclose the 2nd) and i so look forward to his future work.

The worst part of this manga was simply waiting for chapters to come out.

Hope this response is helpful, IM me for questions