This just might be some of the most creative Space Opera You've Never Heard Of. Or maybe you follow the Nebulas, the best SF nominated by other SF/F authors, and you recognize that this is fan service for and by the professionals of the field, and so praise from these people usually means that the writer has Talent. 
 Talent for War, or not, I have to agree in pretty much all particulars. What struck me right off the bat was the heavy elements of Mystery lit. It's solid as hell, in fact. 
 It's merely a strange coincidence that there's models for human minds in VR environments, FTL travel, space battles, and quite alien aliens. It doesn't change the fact that this is a good mystery. Murder is only a part of it. It has a much larger scope when it becomes a post-mortem of an old heroic battle full of buried secrets, espionage, and a complete rewriting of our future history. (Or will it be?) 
 We get to relive the past thanks to the future tech, but both portions of the story, whether it's with Alex, our MC, or Sim, the man who would be an iconoclast traitor. Both were fascinating. 
 But what made this space opera really special? The details. There are so many little quirks of the universe thrown in, from classic (and nonexistent) paintings to truly delightful worlds full of hidden mysteries. As an adventure, there's so much to get lost in and wonder about. As a mystery, the details drag you right into the tale and make you believe. :) 
 At least, that's what it did for me. I'm not a huge fan of space opera in general, but I ALWAYS appreciate a smart tale written smartly, and this falls under that category. It isn't overfull with overused tropes, thank the universe, but it may seem slightly slow to some fans of a certain sub-genre of the SF field because it *mostly* reads as a post-mortem on old battles, from tactics to strategy, with all the reversals of fate and the surprising revelations that the "official" records have squashed. I clicked with it because I like to dig under the surface of things, too, but in this, it's doubly fascinating because of the sheer amount of layers we get to uncover. 
 It's a work of Imagination and care, and that's no joke. 
 I was warned that I might find this slow, but thankfully, it turned out to be just my speed. :) I'll take depth AND breadth any day. :)