Okay so! Some critiques of this book are valid--Butler's engagement with people of color, for example, is extremely minimal, something she acknowledges in the preface to the edition I read. And sure, sometimes it took me a long time to get through certain parts of the text, primarily because I'm not as well-read in psychoanalysis as I might otherwise be when approaching Butler's arguments. But I really thought this was an intense and frankly valuable engagement in the question of gender and the problem it poses feminism. I think there are things to be hashed out, for sure, but the fact that I'm left chewing on her ideas about repetition and the possibilities for agency connected to stepping out of that repetition means frankly the book did what it was supposed to.

So I definitely recommend this if this question is something you're interested in thinking about, and if you are okay with engaging with Butler on this level. Otherwise I guess you can read Susan Stryker's introduction to the Transgender Studies Reader, because she does a pretty good job of summarizing the performativity argument in an accessible way.