I'm not gonna be saying anything that someone hasn't already said here but boy howdy do I wanna talk about these companions, so here's my thoughts in no particular order.
Cait's fuckin perfect. She's got the whole "Best friend but it could easily go further" vibe going for her, which I have a deep-rooted fondness for. Something about both parties just being compatible as pals but always leaving the door open for romance, she never outright says "I love you" but her actions seem to lean that way, idk man it just gets me. She's great. Her grade-A sex scenes, which have just the right amount of bullying, fun, and intimacy involved really seal the deal. She's probably my favorite character in any porn game. No matter what character I try to play, I can never remove her from the party. It just feels wrong without the slutty cat priestess. The past few weeks I always made sure to pop in the discord to see if Savin was teasing anymore CaitQuest, now I can't wait to see it in game. I'm hoping there'll end up being one or two endings where you ride off into the sunset with your wedding-banded hands entwined.
Brint, ho boy. He's a mixed bag for me. On one hand, the idea of a dude you could knock a few back with, high five, and then he'll rail you till neither of you can feel your legs. That's the ideal man right there. Wanna just relax? He's game. Need a spotter? No problem. Wanna go on a rampage through an orc camp? He's got your back. Threesome with a giant snake lady? Say less, homeboy's already balls deep. From the moment you run into him he's willing to risk life and limb to save your soul with nothing to gain and no strings attached.
On the other hand, his dick is just too big. Hyper is a big turn off for me buuuut his romance is still undefeated, so he's firmly in the top 2. (Brint+Cait+PC=Power throuple)
Brienne is meh. Her content on its own is fucking wonderful, Wsan never fails to write amazing and likeable characters, but the fact that you essentially trade Brint in for a different model leaves a sour taste in my mouth. Brint best husbando.
Etheryn, the prime woobie. Alypia already did a bang-up job describing Ryn's appeal, I've got nothing more to add. Love the elf princess.
Quin? I totally get where he turns a lot of people off, but I can't not like him. His sex scenes are great and I want to see his redemption arc. I also want him to cuddle me. Nuff said.
Berwyn, not my thing. I'd love to see more of him where he's less bratty but I guess I'm picky when it comes to dommy femboys. Dick too big, not endearing or interesting enough to make up for it. Fingers crossed that I'll change my mind whenever he gets an expac but I'm sure that's a ways off, B is a busy lad.
Kiyoko, oof. When I first found this game she was one of my favorite characters but over time she's just petered off into obscurity in my playthroughs. Initially, the romance that bubbled up from the Astral plane was the hook that got me invested in the whole game. I couldn't wait to progress and rescue her, made a beeline to the Frostwoods so I could free the floofwife and party with the floofchildren. After the rescue though, the romance just died, her content lost its charm, and it looks like I'm not the only one who felt that way. Being a deadbeat dad with minimal input isn't something I want to be nor something I want any of my characters to be. It just makes me feel uncomfortable and depressed, and not in a "This media has really challenged my worldview" kind of way, it just ends up being a case of "I can't be a decent dad because I'm not given the choice to try." She's easily my least favorite character in the game and I doubt anyone will take that spot from her.
Azzy, another mixed bag. I absolutely adore her wholesome content, I haven't had the heart to try the corrupt route with her. I just wish there was a way to do her quest without sexing her or beating her down. One thing I like about most other companions is there's a degree of separation if you so desire, no sex is necessary to kick ass alongside them or help them out. I just wanna set her up with Liaden and watch the romance blossom without getting involved, y'know? That's completely my personal preference though, and her overall appeal is still off the charts. Buzz gal is excellent waifu.
Atugia, again, I don't have anything new to say. I like her but she's lacking in content, I'll probably like her more when she's more of a character and less of a footnote.
Arona, eh. I prefer content that caters to a switch mentality, so her being stuck as sub or hard-dom isn't interesting to me. I basically only do her quest to get the Bar Brawler title and the chance to bang her sister. Guess I got a thing for priestesses.
Honorable mention, Einen. I want to get my simp on, lemme love the maus already