I've read more of Tocqueville than Custine (as in a tiny amount being greater than zero), and I'm not even sure if the latter was ever translated into English, but from what I have seen of references to the work, it always struck me as an interesting sort of parallel to Tocqueville: 19th century Frenchmen discussing their travels in practically polar opposite countries, through the lens of their own politics. Most of the references I have seen re: Custine were in the context of Soviet history and dealings with the West, and I've been vaguely curious about the book in its own right.