This wasn't what I'd hoped it would be, but I think the fault was probably my expectations rather than the book itself. I'm not much for philosophy; I much prefer history. I was hoping for a thorough, fact-driven analysis of the various totalitarian regimes throughout history, determining key characteristics and similarities. Instead, it's a philosophical treatise on Arendt's view of how the Jews became the scapegoats and how Nazi Germany gained power. Fully one-third of the book is taken up with Arendt's analysis of the rise of antisemitism in Europe. The rest involves grandiose oft-repeated axioms based entirely on Nazi Germany. It talks about the importance of a key central figure and an isolating ideology that includes a sense of exceptionalism, etc, etc, but I can't say I feel much more enlightened now that I've finally (finally!) finished it. And maybe there's a stylistic thing, too-- to me, it felt like her grand assertions were stated over and over, and despite the book's length, there was precious little hard evidence to back them up.
The most intriguing part of the story isn't even told in this book: for all of her stony detachment when talking about antisemitism and Hitler and the rise of the Nazis, Arendt was herself a German Jew who escaped to America. I think I would have found her philosophizing far more powerful if she'd allowed a bit of the human element to seep through.
All in all, while I'm relieved to have finished it, I'm glad I picked it up in the first place. While I found it a dry read, it was still an interesting one, such as her comparison of authoritarian and totalitarian regimes and her assertion that autocratic regimes seek to repress opposition while the core goal of totalitarian regimes is domination and control. While it wasn't a great fit for me, I'm sure it's a phenomenal book if you're a fan of philosophy and have an attention span that's a mile longer than mine.