Okay so I finally finished
the mighty beast of a book and damn what a book. I may have to spend some time getting my thoughts in order on it. Short answer: Probably the most interesting sci-fi I've read in a good while.
Yeah so pretty damn hardcore and impressive. I really liked the slow world building and all the background material that occurs early on, that you feel is just flavour and kind of is, but in a way almost everything features in some way. For a massive beast of a book (900+ pages) its remarkably tight in a way, theres little that in reflection feels loose and plotless.
The whole thing with the avout is also epic, I can see all kinds of influences on them, from various religious orders to various scientific forms and methods, as well as the philosophical input of the dialogues/planing rake/razor. Also the Ringing Vale guys were just awesome ninjas and the Thousanders... just wow. Developing a practice where they seem to be able to kind of pick or influence which narrative/world-track/multi-verse they're inhabiting, hence seeming to rewrite things, developed over time because they basically cured aging/cell degeneration while caring for nuclear weapon stockpiles... awesome stuff.
Also the overall Erasmas/Ala romance actually seemed kind of believable as they slowly grew up over time as the book while in chronological time is quite short (less than a year I think) in personal development time takes them all from feeling almost like kids to being fully grown.
Remarkable effort, well realised world, interesting plot, actually had an ending.