I'm simultaneously amazed by the sheer audacity that Homura displays in the ending twist, and horrified by what she's done. It's not often you see a series end with the coolest character (and main protagonist of the last segment) essentially turning themselves into the devil, and the sheer audacity of being willing to say "screw the universe and everyone else, I want this so I'm going to take it and everything else can go to hell" is crazy. (It probably helped a fair bit that Homura looked even more badass than normal as she was doing it too
).
I wouldn't say that I hated the ending, but I'm not quite sure I can say that I liked it either, my feelings are more "stunned" than anything else I'd say.It would be like if they suddenly released a fourth Lord of the Rings films that takes place after the first 3 where Legolas suddenly reveals that he's secretly forged a new ring of power and rises up to become even worse than Sauron was; you just don't
see that reversal ever happening in stories; it's not your standard good beats evil ending at all (though we do get hints that there might be conflict down the road with that "almost waking" that Madoka nearly pulled). Honestly I'd expect this type of thing more as a prequel origin story from the devil's point of view, not as an epilogue to a story that was already "won".
And add on top of that the fact that even though she's a "demon" she's still not necessarily "evil"? (She only stole part of The Law of the Wheel, so presumably it's still functioning, though maybe not as well, and she apparently represents "love", which while it can certainly be terrible, is usually at worst a tragic emotion, not a "bad" one.) Things get very confusing emotion wise, to say the least.
Also that ending scene made me want to feel sad for Kyubey which was... disconcerting.