I thought the finale was good, but not great, it had a few flaws (some more significant than others) that prevented it from reaching the latter.
The biggest flaw for me was Ymir's "revelation", because even though I can kinda see what Isayama was *trying* to go for with the parallel to Mikasa, the way it currently is presented quite uncomfortable/border-line gross (since it still has a character stating that Ymir "loved" her own rapist/abuser/oppressor), I don't know if it should have been left out per se, but it more really needed to be rewritten in a significantly different manner.
This is how I personally would have done Ymir's "reveal" to be gross/problematic (to put it lightly) while still working as a thematic parallel to Mikasa’s choice: Basically have the revelation be that Ymir was “in love with the idea of being in love and loved” and that her desperate/despairing attachment to such an unobtainable dream (for her) is what kept her trapped in the paths for eons. I figure that can still work as a parallel to Mikasa’s choice and also further parallels to “waking from a dream” that Mikasa went through in chapter 138.
The second other major issue would be the less the twist the Eren (as even though I thought it could have been more interesting for Eren to have stayed a straight villain for the finale, I've been expecting him to pull some sort of semi-Lelouch from Code Geass, for a while now) and more the way the finale has the Alliance characters react to said twist. While the finale doesn't completely exonerate Eren's "plan"/actions, the finale would have been significantly improved if it had its characters be more rebukeful of Eren, at the very least rewording Armin's "thank you" (I know Armin wasn't literally thanking Eren for his genocide of 80% of the world's population, but it was still poorly phrased), like just having Armin say, "I'm sorry you became a mass murderer for our sake" instead of "thank you", would have made so much difference.
Aside from those two major issues, I really enjoyed the rest of the finale (though it still requires some suspension of disbelief in regards to trampling+burning 80% of the Earth's terrestrial biosphere not causing signifiant climate catastrophes, but that's more a series/genre general issue than finale specific).
Anyways, perhaps most importantly, I am definitely glad the series didn't end with Eren "winning" like some weirdos (and many Eren x Historia shippers) seemed to have wanted. Danseru-kun (an older forum member who doesn't visit anymore) I think broke down why there there are so many "Eren is an incel" ~fans~ (beyond being far right dicks and/or misogynists) quite well.
https://danseru-kun.tumblr.com%2Fpost%2F647864529854791680
Also if I was to rank Attack on Titan's arcs right now, this is what my top favorites list would be right now:
1. Clash of The Titans arc
2. War for Paradis arc
3. Marley arc
4. Return to Shiganshina arc (including Grisha’s flashbacks)
5. Ragnarök/Final arc
6. Beginning/Battle of Trost arc
7. The Uprising arc
8. Female Titan arc