Yuma is either viewed as The Woobie and Kyouko's necessary surrogate sister/adopted daughter, or a Bratty Half-Pint who should have been cut out of the story. While her situation is undoubtedly horrible, whether you find her cute seems to vary from person to person. Her Rousing Speech is either her crowning moment or bizarrely out-of-character.
Just how justified Oriko was in her actions remains a topic of debate, particularly given that she's viewed as something of a martyr by people who dislike Homura. Her portrayal in fanfic varies between A Lighter Shade of Grey to a cackling murderer. Her design gets some of this as well; some find the Pimped-Out Dress and Nice Hat to be probably the most beautiful outfit of any series, others think it looks silly and refer to her as "buckethead."
Kirika is either Crazy Awesome and a great deconstruction of the Manic Pixie Dream Girl, or a pile of Wangst who's nuts for no good reason. Her relationship with Oriko was either one of the best-explored romantic relationships of the series or really, really creepy (though few would call it a very healthy one).
Better Than Canon: Pixiv user nobita's two-part comic "Girls and the End of the World" (1, 2, English translation (missing a few pages)), which focuses on the conflicts between Oriko's and Homura's opposing goals and motives, with absolutely gorgeous art. Many people are surprised when they see pictures of it and find out it's not from canon.
Draco in Leather Pants: Following Rebellion, "ORIKO WAS RIGHT" ended up becoming something of a meme due to Oriko predicting that Homura would despair, and finally go to insane/irrational lengths to protect Madoka. (However, Oriko was trying to kill Madoka (who quite literally made the world a better place in the anime) while viewing Homura only as an obstacle to that goal and not a danger in of herself)
Epileptic Trees: Started the very moment the cover was revealed. The major topics were about when Oriko Magica takes place, and whether the new magical girls introduced in Oriko Magicawould become witches that were seen in the anime.
Ensemble Dark Horse: Yuma also pops up in fanfic, and she appears in licensed (Japan-only) parody comics. Apparently, a lot of people thought Kyoko should have a little girl to take care of. Magia Record even has a pixelated Yuma sprite in Kyoko's transformation sequence.
Evil Is Sexy: Yuma's mother Mako seems to have a nice figure, large breasts and subjects her daughter to vicious physical and verbal abuse (and in an official spin-off off the spin-off, she even ended up killing Yuma in one of Oriko's visions).
Though some fans happily accept both, people who liked Puella Magi Kazumi Magica seem to hate Oriko, and vice versa, given that they're very different takes. Fans of the Kazumi call the Oriko an ugly, pointless, meandering sidestory that does nothing new and borders on unreadability, versus a lengthy and detailed narrative with great art and tons of characters that stands on its own. Fans of Oriko call Kazumi a skeevy, character-overstuffed, overlong piece of pap that reads like a mix of a Dolled-Up Installment and a bad fanfic, versus a dark and deconstructive tale that introduces the best Canon Foreigners of the franchise and makes great use of the original material.
There are also those who think both series are equally inferior to the anime.
"Funny Aneurysm" Moment: In a flashback, after a young Oriko pledges her efforts to help her father, he offers her a reward, and she says, "Daddy, you can't give out bribes!", to which he laughs and says she "got (him) there". Taking money that doesn't belong to him, on the other hand...
Harsher in Hindsight: Quite a bit of things from Oriko are reminiscent of things from Puella Magi Madoka Magica the Movie: Rebellion, even though it's probably coincidental. The things include *WARNING REBELLION SPOILERS* one of the mains taking someone under her wing, a witch barrier being created before the magical girl becomes a witch, Homura's insistence on saving Madoka against her wishes, and almost everything about Kirika Kure. Finally there's the matter of Oriko's vision at the start of the series. While it's supposed to be Madoka's witch, it doesn't look much like Walpurgisnacht or Gretchen. It looks more like a black human figure in a dress, with long hair and/or wings...
It is human emotion that created the gods and created the demons.
Heartwarming in Hindsight; Mami and Kyoko's interactions in Oriko Magica can be seen as this after listening to the 3rd drama CD and/or reading The Different Story spin-off. Despite their partnership ending sourly in the past, the two manage to interact in civil terms, in contrast to The Different Story and the PSP Portable game, where their reunions were more hostile. When Mami meets up with Kyoko, she warns her about the Magical Girl killings, and Kyoko doesn't hesitate to bail Mami out when Oriko and Kirika take over the school. Then there's their victory fight against the witch Kirika, which is more poignant if you consider this is their first witch fight together in a long while.
I Am Not Shazam: Oriko is often confused with Yuma, the little girl with green pigtails who appears of the cover of the first volume.
Oriko and Kirika, who value each other above anyone else. Not to mention that Kirika's wish was to change her personality just so Oriko would like her more, and Oriko viewed Kirika as the only person who liked her for who she was, rather than associating her with her family or her father.
This quote confirms it:
Kirika: Treating me like a child again! Really Oriko, I-
Oriko: " Hate you"?
Kirika: I love you!
This, combined with Foe Yay, undertones Mami and Kirika's relationship.
Due to the art-style, some things are really hard to take seriously. For example, Yuma just saw her parents killed right in front of her, and she's wondering where she's going to go. It's a really sad scene, until... she makes this face (bottom right panel).
Madoka just saw her teacher being eaten alive, the witch familiars are attacking everyone, and has been separated from her friends... and reacts by making a cutesy face (bottom left).
Madoka's death. Even though it was a Foregone Conclusion due to this being a previous timeline, the last scenes had set up a Hope Spot for her survival. Also while in other timelines, only Homura was there to see her death, here we get an audience from Sayaka, Hitomi, Mami, Kyoko and Yuma. To make things more depressing, Word of God states that Homura can only turn back time after a month has passed from her discharge from the hospital, meaning that she had to dwell on her failure to save Madoka in this timeline for days or weeks.
Kyouko's thoughts as she thinks she's about to get killed, regretting that "it sure was a rough life" and wishing she could have had a good dream once. Her being neither happy with her life nor able to accept her own death is quite depressing.
They Wasted a Perfectly Good Plot: After the Rousing Speech by Yuma, Mami promised that they will make Kyubey pay for tricking them after they beat Oriko. But then Homura rewinds time before that happened because Madoka died. Dammit, Homura.
Uncanny Valley: Kyubey is drawn like a plush toy with a fish-like face, instead of his usual body shape, making him look downright deformed-looking.
Win Back the Crowd: Extra Story seems designed to do this: the plot is considerably more focused, the art is better, and it fleshes out Oriko, Kirika, and Yuma a lot more (while also giving the former two a good amount of Pet the Dog moments).
Yuma. Poor kid deserves a lot of hugs and comforting for all the trauma she's been through even before the story began.
Jerkass Woobie: It doesn't take long for Oriko and Kirika to enter this status either.
It's hard not to feel a twinge of sympathy for Oriko when we see a flashback of her sitting all alone in a corner of her vandalized house, wrapped up in a bedsheet with teary eyes after her father, a politician, committed suicide after it's revealed that he was embezzling funds. Everyone turns against Oriko, leaving her completely alone (which is bad enough in and of itself, but it also implies that the only reason they hung around her was because of who her father was). Cue Kyubey's entrance. This is made even worse in Sadness Prayer: Oriko's father was disowned and shunned by the rest of the Mikuni family and only entered politics in the first place because he recognized Oriko could be a world leader someday and was trying to earn his father's approval again so he would sponsor Oriko, only to be betrayed by him. Oriko learning this leads to a great Despair Event Horizon where she nearly kills her grandfather and needs to be talked out of succumbing to despair by Kirika.