I noticed recommendation for "Too Like Lightning" in some thread here, and decided to read it mostly on a whim. Some other comment compared it to Lois Bujold's books, but that's a bald-faced lie - it's hard to imagine two writers more unlike than these two. Ada Palmer is much, much closer to Ian M. Banks, both in readability (which suffers sometimes, though for different reasons), and in imaginativeness of the world-building (Bujulod's books, while great, present somewhat generally generic space opera world). Actually, in my head-canon Terra Ignota series is now a prequel to Culture.
What also makes Banks' and Palmer's books so like each other to me is that they both describe what can be considered an Utopia by modern standards. This is a very rare case in modern sci-fi, which prefers various shades of dystopia or more mundane "space empires". The world of Terra Ignota is a FLAWED utopia, but it would be very hard to call it anything but that much-maligned name: at the beginning of the first book, the world was at peace for more than 300 years, people only have to work 20 hours a week, and they have flying cars that can deliver you anywhere on Earth in matter of several hours. There is no tyrannical government, no secret police or prisons, and the only underclass - Servicers, sentenced to free labor for common good because of their crimes - still fare better than modern-day criminals rotting in prisons.
It's not ideal - for that matter, this still a long cry from post-scarcity AI-driven world of Culture - but it's better than most sci-fi worlds. This is a world where one might wish to live instead of our age. But it could be better, and this is the central conflict of the book - which makes it almost absolutely unique by my count. It's very refreshing to find a world where competing factions are not white and black, or gray and gray (a very overused trope these days). They just have equally appealing (with some caveats I'll get to later in section with spoilers), but absolutely incompatible visions for a better future. This is not even a stability/progress conflict, which also appears in media from time to time, but a pure confrontation of different progressive ideas. I can't gush enough about how happy I am to finally find a book with this type of central conflict.
There are a few things, however, that prevent me from declaring Terra Ignota series from being the best sci-fi of the last decade (it's still a strong contender, and I'm not sure who would be a winner). The first is writing. It was a problem for me in Culture series, too - Banks can be a bit too dense and slow at times, but Ada Palmer is just too in love with 18th century. Parts of the text are stylized as a kind of philosophical text from that era, or maybe a diary. In this case, it means a lot of "thee", "thou" and "dear reader". The gimmick grows stale even before "Too Like Lightning" ends, but she keeps it up through whole four books, much to my annoyance. Also, the narrator, for the lack of better word, is a whiny baby. The amount of time he spends crying and/or apologizing to "dear reader" in those persistent asides is grating. I get it, he's a broken man. Could we all accept this point and move on with the story already, please?
Also, this might be my personal problem, but I find endless discussion (and switching on the fly!) of characters' genders tiring. Yeah, this nice world of future doesn't care much for genders, but the narrator does, because he imitates 18th century when that stuff was important, and it's kind of a important plot point, but there is just too much of it.
Another point I'd like to make about this series is neither negative, nor positive by itself, but its interpretation will depend a lot on your preferences. Sometimes it feels like Terra Ignota books were written to be televised by an old-school cable channel. Because they have so much sudden, but evenly spaced plot twists I almost can see an ad break after each one. I was OK with that - those are good, fun plot twists - but I can imagine someone might find this style of storytelling annoying.
This, I think, is as much as I could say without spoilers, so if you're on the fence about trying this series, I urge you to stop reading here and make your decision. Personally, I recommend at least trying it, but be prepared for some parts that might be a slog. You will have to power through them, so if you're not the kind of reader who's prepared to suffer a little for an interesting plot, maybe skip this series then.
--- SPOILERS AHEAD ---
OK, and now, here are some things I'd like to vent about concerning this book, mostly to other people who read it.
One is purely technical, but kind of important. It feels that Ada Palmer decided to use some fantastic technologies for her world without fully considering their impact. For example, the very basis of the Hive system, Mukta flying cars. For one, they break laws of physics, or posses way more technologies than described. They can reach any point on Earth in a couple of hours, which means they're hyper-sonic. How do passengers even survive that? The actual flight of a car is never described in details, but I think for the whole tech to work this world must have mastered anti-gravity or some such technology. And yet, their best way to get into space is a space elevator?
Also, these people have human computers, set-sets, who can "feel" any data as a man would see, touch, smell and hear physical reality. Only more so, because they have, like, 40+ senses. It's a major plot point that these set-sets can see a looming crisis that would lead to war, or dissolution of the current political system, and the way to prevent it. By killing a single citizen. But why? O.S. (the secret organization/family/"bash" that's charged with this duty) is never described as anything, but a group of assassins, but surely a lot of crises could be defused without killing anyone if you can spot them early enough. A huge part of the plot is that the world should, after O.S. is discovered, to learn to live without their stabilizing effect, but it should have learned to do it long ago. It's really hard to imagine that in 100+ years of O.S. activity nobody tried asking a question "do we need to kill anybody to fix this?". I guess some explanation for this could be invented, but none is given in all four books.
Of course, this series also has literal gods walking the Earth, reviving dead people and turning parts of reality into Iliad re-enactment IN SPACE, so maybe I shouldn't be so harsh. This is not hard sci-fi by any means. Sill, it is in my nature to wonder about such things, so I do.
And another thing. The book have two major conflicts: Remakers vs. Hiveguard (those who want to change the world so killings by O.S. are no longer needed, and those who are ready to accept O.S. methods as necessary evil to preserve the current system), and Brillists vs. Utopia (those who want basically human/computer singularity vs. those who want space exploration). These conflicts are presented as fundamental, and yet...
How can the world with O.S. in it continue to function when everybody already know about this organization? Even if everyone will consent to be killed for the greater good (which is, let's say, is highly unlikely), the very knowledge of existence of O.S. will wrap all their calculations now and forever. It's impossible to put this genie back into the bottle. I can appreciate the impulse to preserve status quo - the Hive system, Alliance, etc. - but O.S. cannot be saved, and yet nobody in the book ever makes this point clearly, much less discusses it thoroughly (while they do discuss a lot of other things).
Now, for Brillists/Utopia conflict. It is GOOD. I love it. It's very basic in its nature, and yet, so very powerful. "Let's become immortal, then maybe go to space" vs. "Let's go to space, and then maybe become immortal" might seem like a small difference, but it's actually two very different ways forward for humanity, and this is explained well in the book.
But I do have a small nitpick anyway. While Brillists make a good point about combating Death before anything else, they never seem to consider a small, but not non-existent chance that Earth, or even the whole Solar system can be wiped out by a cosmic event at any time. I mean, this is a thing we worry about NOW. Every year spent without spreading humanity beyond our home planet is a risk. Actually, neither side seem to consider it - Utopians want to go to space because it's cool, not because it's a survival imperative, but Brillists simply ignore this, once again, without even discussing it. This makes their position just so weaker for me - which is a pity, because otherwise, I found both sides of this conflict almost equally appealing, making for a great "good vs. good" confrontation (er, barring some late-book atrocities by Brillists, but then again, Utopia aren't snow-pure angels, either).
Well, that's about all I have to say. I think I had some nitpick against Utopia, too, but I've forgotten it. Anyway, I enjoyed this series very much despite its drawbacks, and if anyone else can recommend me more books with the same type of conflict, I'd be very grateful.