So the thing I didn't like about Among Others -- well, OK, it's not just one thing:
(1) First and foremost, the biggest events in the storyline of the book either (a) don't appear on the page at all and/or (b) take only a page or two in the whole novel; *these* are the interesting things, that I would like to read more about, and they're not covered by the author (but you would read about them in a synopsis or cover blurb and then be disappointed in how the book, itself, treats them).
(2) On a related note, instead we read tons of lists of books the main character requests from the library, plus lots about the squabbles that go on in a girls' boarding school (I don't give a rat's behind who sends rolls from the bakery to which girl this week and what it says about their supposed friendship or lack thereof -- it's not important); it's like reading a teenager's blog.
(3) This is pretty minor but it grated on my nerves -- the POV character constantly says she's not good at math but is good at chemistry. I know from personal experience (as in, I have a BS in chemistry and a PhD in biochemistry and have been a TA for many college and graduate level chemistry classes) -- you cannot pass a chemistry class if you can't do math. Probably I would've overlooked it if I had been satisfied with the rest of the book, but since there were plenty of poor decisions on the author's part, with respect to story structure, it's just one more thing to tack onto my list.
One could argue that the main character is an interesting study, that she was warped by interpreting her family situation through, for example, the writings of Heinlein. But you'd have to stretch. Because it really does seem to be all about bakery buns and classes and convincing one's aunts you don't want your ears pierced (and bizarrely strong feelings on both sides of the ear piercing discussion) and so forth.
I think all the hype was because of the nostalgia value for the awards voters.