In Japanese, "Kitchen" is not the kitsch piece of trash the English translation makes it out to be. Even so, I'd hold off reading "Kitchen" until another translation appears, unless you can read it in Japanese.
Here's why:
As others have said, the translator took some liberties and manhandled the feel of the novel. In several cases the translator (Backus) completely removed sentences (does a 100-page book need abridged?), and in other cases replaced prose, elegant in its simplicity, with cliche.
An example of the latter is the very last sentence of the second part, "Full Moon" (this isn't a spoiler). In Backus's translation: "I launched into what time I'd be in and what platform I'd be on." In Japanese, it's literally "I started to explain my arrival time and what platform I'd be on." I can't remember the last time I got so excited I fell out of my seat and "launched" into telling someone something mundane like I was going to be home at 3:20pm.
It's the gross overuse of cliche in the translation that destroys that fragile atmosphere Yoshimoto Banana created in the Japanese prose. For example, when a page is filled with a few precise words, it's like a Monet painting: hundreds of tiny strokes carefully arranged to create a greater image. But to translate those emotionally-loaded carefully chosen words into goofy cliche is to take a Monet painting and make a few strokes with a floor mop. Spare yourself of this translation.