They are definitely not easy to understand, at least for me, they are just easy and pleasant to read, but it's deceptive. Once you go to the exercises and try to work out what Feynman meant really precisely and how it applies you realize how big reasoning leaps he does all the time in the lectures. I mean, years ago, I read the full first volume once, almost like a work of fiction, it just was pleasurable, but I understand almost nothing, except for the first few chapters of general introduction. I came back after 10 years to it with much more math background, and it's still really really difficult to understand what Feynman is doing and why and solve the exercises. He is the kind of author that will make you almost angry, several times I thought he must be wrong in something, and then an hour later you realize he was exactly right but he choose the most clever way to put it. On the other hand, if you are not struggling with a textbook, you are just memorizing, not learning, so maybe it's not a bad thing, I can't really say.

As an Indian, this is something I have been very glad for. Almost every book has a South Asian edition which is super cheap and just as good (so long as you don't have graphs that use colour).

I had access to everything because if I skipped out on a couple of movies, I could buy this whole set.