I thoroughly enjoyed it, learned a LOT from it, and while I read a library copy, I'm hopefully going to get my own copy to have on hand to use as reference.
The translation by Yoshihara and Winters-Carpenter is absolutely beautiful, and despite some very minor things (mainly Japanese as a noun when it should be the adjective of a noun ("a Japanese" instead of "a Japanese person")), the English text has none of the 'tells' of being a Japanese translation many other translators mess up on.
The last few pages (around 180~200) were uncomfortable in that Mizumura really injected her personal politics into the writing, when she could have written more neutrally on the subjects. I also disagree with her assertion that being able to speak a language is what makes someone Japanese, or any group that could be applied to. There's more to ethnic and national identities than understanding a language, especially when it comes to nations that have more than one local language (Especially considering Japan has more local languages than simply Japanese, albeit not as widely spoken.)
I do agree with her conclusions at the end about the importance of learning foreign language as mandatory education, and that native English speakers need to especially learn foreign languages, and recognize the immense privilege brought by being a native speaker of the most widely spoken, and most globally important, universal languge.