Some of the thoughts evoked by the author are very deep and insightful. If you enjoy GW's series, it will help you to find some new levels of appreciation for the cleverness. Reveals some of Severian's relatives... the clues were there, but I never noticed them.
But.... some of his ideas are just nuts. The part I dislike is that if the author does not know the answer and cannot come up with a clear deduction, he'll almost make it up. While he uses text from the book, he will almost (not literally) try to prove red is truly green "because they are opposites and that's the key! Yes, the key! So, during Christmas... um, they go together... and it's a Christian holiday, so OBVIOUSLY Gene Wolfe meant for us to see that!"
Good to read, but take it with a grain of salt. I'd prefer less reaching and more "I just don't know"