Good although a bit inconsistent.
The story starts out strong, with Harry having to deal with the aftermath of the war, working as an auror and trying to deal with the remaining Death Eaters. Much to his chagrin, the wartime tactics of going in and blast all of the bad guys is no longer acceptable when some of the former Death Eaters have admitted to their crimes and stated that they were essentially under a death threat. The plot thickens as Harry and Hermione have to fight rumors that they're having sex (which they are) despite their respective canonical engagements. From there, it gets really weird as Hermione finds out she's a Crouch (there's an entire department at the Ministry of Magic devoted to covering up cases of wizards raping Muggles and then obliviating them), Harry gets caught up in politics with the help of the Malfoys, and relationships spectacularly explode. In the end, the author meanders their way to the canonical epilogue while leaving us with the impression of a Peyton Place Wizarding World where cruelty is overlooked, infidelity is the standard, education is overlooked, and half of the population is blissed out on potions.
Despite that, it's very good. You can understand why the characters take the actions that they do and the world is built very plausibly. The extreme plot twists... basically are the result of frustrations of an author feverishly trying to follow canon even as Rowling repeatedly changed her mind in interviews. The downer ending feels almost justified as the author finds he has to resort to drugs and chicanery to make the canon relationships work. The characters aren't saints, but they're not irredeemable, and you can trace a lot of their issues to growing up in a world where they were pressed into war as Child Soldiers
and their inability to live in the resulting peace after they win.