I mean: majority true VN players would prob pick Ao or Shiki.
for... reasons that may go into spoiler territory.
as far as the anime goes: only Shiroha and Kamome have gotten much chance, so...
This is true because if we look at the favorites numbers before the anime arrived Ao was more popular than Kamome and considering that the poll was created in January then Ao had started ahead of Kamome being behind only Shiroha both in favorites and in the polls but thanks to the anime buff and screen time Kamome ended up passing Ao both in the poll and in number of favorites currently being at 158 while Ao has 152 and since most who added Kamome only saw the anime and still don't know about the others then it is normal that at the moment she is the most popular (although she is still in second place) and this buff will also happen when Tsumugi gains more screen time like this and will gain more favorites and votes in the polls and when Ao's turn comes I believe she will pass Kamome again given how praised her story is and she will become even more popular and when Shiroha's turn comes I believe she will be the most popular with the buff of her route and also with Alka and pocket which is where she will have more screen time and more development beyond her emotional moments with Umi and Hairi, and if Shiki is highlighted in the anime I believe that the final result in the enuquetes and favorites will be like this:
Shiroha>Ao>Shiki>Kamome>Umi>Tsumugi>Shizuku>Nomiki
However I think that Kamome and Shiki will have a balanced dispute.
While I see VN readers giving preference to Ao as the best girl, anime companions seem to like Kamome more, but regardless of that I think everyone knows that Shiroha will become the best girl in the end.
@EienGem It is because many like her from the visual novel.
Basically, she starts out as this obnoxious character always lying on the ground ready to pass out due to extreme hunger when passing by early in the various routes and you can just ignore her or whatever. She doesn't show up in the other routes really beyond that, except the true end where she is extremely important but is partially hidden so if you don't pay attention you will not realize it is her as you just hear her voice when she saves Umi from being lost in time (aka, the stuff coming up soon in the route when she goes further into the past, Shiki is the one that guides her). Shiki is also the one who allowed Kamome to awaken from her final coma in her ending.
However, while her route initially seems very weird as she calls herself an Oni and extremely ridiculous or childish it grows quite far beyond that.
Initially it is goofy and she is looking for her memories cause she has amnesia, but as you progress in the route...
Spoiler for those who plan to read the visual novel, but it will not be covered at all in the anime it appears:
You find out why she is called an Oni and that she actually is from the distant past, either decades or hundreds of years into the past on this island (I forget how far back exactly). There was a massive tsunami she knew would come and she basically tried to warn the inhabitants of the island she lived on to protect them so they would get to higher ground. They took her warnings as a joke and ignored her.
She ended up creating a false pirate invasion at sea with some tricks to make the village (like I said pretty far in the past) think they were being invaded to run up the mountain fleeing to higher ground away from the shoreline and lower ground. She did this knowing that not only would the island inhabitants hate her and called her an Oni, but that she would die in the tsunami.
The story flips back and forth between her past / current timeline in the later portion of the story. Eventually, MC and her are sent to the past and MC tries to save her, she basically confesses her love but he gets sent back to the future as she does not shy away from sacrificing herself to save those on the island in her second chance... She dies, once again, and is the guardian of the island henceforth looking after it. There is a statue erected after her, too, iirc.
Honestly, a pretty brutal story all in all and gets quite emotional later on. Shiki's extremely light carefree moments and sides starkly contrast to her extremely serious self-sacrificing noble character. This ties into some of the story's core overarching lore, the butterflies, etc. While all the routes end with a potentially positive interpretation, except the true end in the original version (happy end in Reflection Blue extended version), Shiki's is extremely emotional and a bittersweet and devastating, yet proud, ending.