I can post my personal reviews/thoughts of some fansubbers if people want, based on my limited experiences with some of their releases.
I won't be reviewing things like video quality/source since I'm not qualified or autistic enough for that.
>Infusion
They did the best available fansubs for Hajime no Ippo (the first season) in terms of translation. Good styling, weird karaoke (but its appreciated nonetheless), word choice and tone that fits the work overall. They talk like boxers and that is conveyed well, whereas in other translations and official TL rips, they have them talk like stuffed shirt faggots at times.
>Anime-Empire (A-E)
Did the best fansubs for Yakitate!!. A shit-ton of effort was put into things like TL notes to explain a lot of things since its fairly technical. Had a nice and appealing style and felt natural to the work.
>Some-Stuffs
Basically the successor to Mudasubs for Jojo Parts 1-3, had some damn good subs. Great style for Jojo, good aesthetics. Wish they had karaoke but the fonts were nice, dialogue felt good to read and go through and punchy, suited for Jojo.
>Hatsuyuki
Meh, I wasn't particularly impressed with their One Piece subs. Not much style, and it just felt "normal" otherwise. It was fine, and considering they're the only option available for post-Dressrosa, its whatever. I didn't notice anything too glaring, its just "okay". Probably better than CR, but who knows.
>Saizen
Solid subs for Kuroko no Basket, could've used a bit more style in the regular dialogue, but it felt pretty normal. I like their karaoke and signs. I expected them to be overly verbose but thankfully its fine.
>Kantai
I didn't have issues for their subs for 86, its been a while but I think it was nice enough.
>Asenshi
I don't remember much about 'em for what they did, I watched Made in Abyss through them. It was probably fine, I dunno.
>Black Order
best subs for TTGL and D-Gray Man (not sure why you'd care on the latter though)
>Kaizoku fansubs
By far the best one piece subs, but everyone knows that. Great TL notes, wording, styles, translation, tone, feel, good attack effects, and it was just made with a lot of soul. Once you're done with them, move to Vegapunk and then Yibis and finally Hatsuyuki. Vegapunk and YIbis are good, a bit worse than K-F in small, subtle ways, but good enough to continue at least. Hatsuyuki is unimpressive, but acceptable.
>FroZen
they worked on a later season Hajime no Ippo, felt it was too overly verbose and technical, did not flow well and was awkward.
>Underwater (or CH)
Not sure which one it was, since its not easy to check, it was most likely Underwater, but they did some great subs on Kill la Kill. Good translation choices generally, and they translated the signs in a very creative way that fit perfectly with the anime.
There are others I could mention, but I'm unsure if they are just official sub rippers or not who just basically change the font and that's it.