I read the final volume of Amanchu yesterday, ending a journey that started 12 (!) years ago. It was a bit sad to say farewell to Teko and Pikari, but I'm glad to see a manga I've been following a long time ending on the mangaka's own terms. Amano got to do what she wanted with it.
The final volume was really interesting, switching the POV to Pikari entirely. The yuri undertones came back full force. The character that grew the most over the course of the series was of course Teko, who has completely come out of her shell by the end of the manga.
I loved this manga very much. While it lacks Aria's charm, it's still very good.
Since we're in the manga thread now, I'll post some stuff under spoiler tags
Spoiler for Final volume:
The role reversal from the first volume was very interesting. Pikari tried to spend as much time with Teko as possible until her departure for Tokyo after graduation, and every time they couldn't see each other because they were busy, she felt really lonely. The yuri moments I was talking about were Pikari confessing her love to Teko (I don't know which exact words she used in English), her thinking over and over how beautiful Teko's hair is, and when they slept at the same place, she thought she's always loved Teko's smell and that it's a secret she can't tell anyone.
Their last day together was fantastic, and their final dive was at the place of their first one: the school's swimming pool! There, Teko made a speech about how a human's cells constantly get replaced and that she isn't the same person Pikari met three years ago. The reason she never cut her hair is that she didn't want to admit it, and she proceeds to cut it off! Her new haircut is a bit like Aika's.
When the time came for Teko to leave, everyone sees her off at the bus stop and Pikari goes as far as the train station, but she can't bring herself to say goodbye and jumps on the train at the last minute! We then cut to a scene with Grandma and Kodama where Grandma states that while it was the other way around at first, Pikari had become dependent on Teko. Teko gives her a speech and a "riddle" to solve and she gets off at the next station.
The manga ends with Teko making a surprise visit a few months later and they hug in the water. No kiss or anything of the sort, of course. They give the same answer to the riddle and it ends.