After needing to take a 6 week hiatus when I left my kindle at my parents place, finally got round to finishing Citadel of the Autarch (book 4 of Gene Wolfe's Book of the New Sun). I guess I'm now in a position to comment on the 4 books that taken me 18 months and lots of breaks to get through.
I can see how a lot of people would get put off by book 1 (Shadow of the Torturer). It's really dense prose, unreliable narrator and a load of stuff that's not explained until later on in the saga. Book 2's revelations and the nature of the Alzebo completely turn how you look at book 1 on its head. At the end of it, you're in a dilemma re: whether to go back and reread book 1 or to continue. At that point, you think the main character may be autistic and has a really weird/ disturbing way of conducting his relationships with women. One of the hard bits is that you're not rooting for this protagonist.
The third part (sword) is probably the strongest of the series. You get the feeling of 'I spent 2 books figuring out how to read it, this is the payoff'. A lot of the epic scenes are here. Book 4 starts with a load of short stories and then meanders in comparison. Yes it expands the scope but it's not as strong as the previous iteration.
Aware this initially one book, then split into 3. Then the 3rd part got split into books 3 and 4. Can't comment on book 5 which came out years later at this stage.
This is a story that can only be told in book form. The prose is lovely and when you look deeper, some of the concepts alluded to (though not directly) are huge. Planes of existence, the nature of mortality, homunculi, some people living time in the other direction, etc. It's really good for those who love discussions and thinking about texts from multiple different angles. But it's not a linear rags to riches type of plot and as I've said above, character focused readers probably won't enjoy it.
Will pause in this journey for now. Perhaps read book 5 in a yr or 2 before even thinking about a reread.
Next up, I said I'd read Watership Down (Richard Adams) with a friend.