You know what, enough people have been giving the full list rundown of companion opinions that it's gotten me itching to share my own thoughts on them all. As a departure from my usual way of conducting myself, I'll be letting way more personal bias seep in here and speaking from the rotten chest cavity. Bask in the terrible glory of my sleep deprived ramblings.
They shall be listed from least liked to most.
Lean more towards dislike
Quin - Kinda was into it, but I can't separate him from association with his writer's behavior, so it's a pretty big turn off. And since my interest was purely of the gremlin variety and not really being into them from a writing quality perspective, that means there's practically nothing to grab onto anymore here for me personally.
Brienne - appeals to absolutely none of my interests aside from gender transformation/transitioning if written well or creatively, the act of getting her is morally kinda fucked if I'm really getting into a playthrough, sacrifices Brint who I like a good bit, and overall is just something I kind of forget is even a feature in the game 90% of the time.
Viv - is something I forget is in the game 100% of the time until reminded of it on here, at least in companion form. She's still new so naturally a bit light on content, can't judge too much, but overall she's not really a type of character I will be much interested in no matter the amount of smut. Sometimes something just isn't for you.
Arona - subs okay I guess, hate you can't pull rank and try to curb some of her more problematic outlooks/interactions with other individuals or force her clan to not be a marauding band of murder rapists, dom arona can jump off a bridge. A bridge over an interdimensional portal to the lawnmower dimension. And yes, I know some are into it, and no shame in that, but I stand by my armada of infinite lawnmowers here personally.
Kiyoko - Necessary to access wholesome farmer fox daughter, so of some worth. Some of her scenes are kinda nice and romantic too, but overall she's very much not for me which is why she's down this low. Also hate the dick gating and lack of interactivity with other companions. Necessary for my beloved miserable grump champion portrayal though.
Lean more towards liking
Azzy - Love base Azzy, except for the Lia content if you're wanting to do the big romantic with cute bee woman. Not really into threesome content all that much, and when that's not the case it kinda feels like you get the shaft as far as how the relationship went. Kinda wish there was an option to tell her to go for it with Lia whilst opting out of seeing some of the content, the opt out as it is now was written in a very backhanded manner. The B I G bee is not for me though.
Atugia - Content light, but she has a neat design. She's strong, she's got spectral halberds, some cute interactions, it's not bad. Not enough focus on being a headless abomination though.
Cait - content wise, it's hard to compete with Cait. She's pretty much the quintessential companion, though I wish more of her scenes hinted at the possible romantic feelings she has for the Champ. Until things get more rommy though Cait's just a really fun, cute character with a lot of smut options that happens to work for a shithead god. I deduct points for that last bit.
Ryn - The bringer of death, the illusion of hope, the fucking walking icecube. Ryn is aesthetically adorable, in personality she's the same way, her relationship with the champ is the best written one in the game at this point. But in my experiences as someone with issues retaining body heat, I generally want my partners to run a bit on the warmer side so I can leach heat off of them like a fucking vampire. I have absolutely zero frame of reference to imagine snuggling something cold as being anything but awful. Love her story and arc though, so for many of my characters Ryn is the precious little sister that must be protected at all costs.
Brint - Effectively the only male companion, so automatic rise to the top. Nice bro and a lad, some of his scenes are sweet when you get romantic with him, said romance is kinda handled horribly at times, his genitals are terrifying. Big ol' axe doesn't hurt.
Agni - WARM. Love bards, love fire, love birds, did I mention WARM though? Agni has a fun skillset and personality, a bit weird that she's immortal, it's not written horribly but it should probably be a bigger deal to characters other then Agni herself, though she's still relatively new. Her bust is very pretty to me personally as well, which is a point in her favor. Needs more smut content pronto, but she's damn warm so I'll take it. Run the funny lovely fire bird 24/7.
The Tomb of the King
Berwyn - Most attractive (former) companion in the game, fun bratty personality unless you let him go full dom(then it's a slap upside the head), his dick was too big but letting him use it was recipe for disaster anyway so nothing lost. Summoning rocks to punch people is one of the most worthwhile uses of magic. Ran the little shit in my party full time despite being a bit mediocre combat wise. But alas, twas not meant to be.