It's okay. I watched all of it. I might watch Season 2.
Garo is a live-action tokusatsu franchise, but slightly unusual in being horror-tinged and aimed at an adult audience. ("Tokusatsu" means "special effects", but usually in a knowingly goofy way that suggests stuff like Godzilla or Mighty Morphing Power Rangers.) It started in 2005 and it's been very successful, with lots of TV series, films, specials and now also this anime.
It's set in a fictional European country called Variante that's a bit like Spain during the Spanish Inquisition. Torture, witch hunts, etc. It's all there. Our heroes are Makai Knights, who are superheroes who transform into magical armoured warriors, but unfortunately they're being hunted down and executed on the orders of the king's evil advisor Mendoza. He doesn't like them. It's not clear how he got the king to agree to this, since Makai Knights go around destroying Horrors, which are demons that possess and devour humans. Anyway, our hero, Leon Luis, is one of those Makai Knights and the latest one to hold the "Garo" title. There have been lots of them. They hand it down from father to son.
Leon's introduced to us as a baby. A witch gives birth to him as she's being burned at the stake, then he gets snatched to safety by his father in his Makai armour.
Overall, it's a decent series. There's a lot to like here. The horror stuff is juicy, with several enjoyably evil episodes. The Innsmouth-a-like village of ep.4, the ghost story of ep.14 and the medieval plague doctor moral issues of ep.16 are all well worth your time.
Similarly, the plot occasionally has some pretty extreme developments. If anything, it's erring on the side of going too far. I wasn't always convinced that these twists were as well written and plausible as they could have been.
The show's main problem, I think, is its tokusatsu roots. At the end of the day, it's a show about demon-fighting knights in CGI armour. The horror stuff can be great, but then it inevitably turns into a story about a big goofy monster. Demons are bad. They eat people. No argument there. However they're still a bit disappointing compared with examination of the vileness that ordinary humans have proved themselves capable of.
Similarly I never really got excited about the fight scenes. They look good, mind you. The CGI knights have spectacular designs and it doesn't matter that they're not cell-shaded. However they're generally just the genre-mandated killing of the monster of the week. There's a fight scene every episode.
The characters are okay. Leon is an intense teenager with absolutely no sense of humour, but the storyline has some extreme developments in store for him. I approved of those. That's the best thing in the show. Alfonso is a good, conscientious person and that's about it, really. Ema's okay. (She's also wearing Aoshi's coat from Rurouni Kenshin. You could land helicopters on those lapels.) Mendoza's what you'd expect.
No, the two characters who stand out for me are one of the villains (Octavia), who has strong motivations, and Leon's prostitute-crazed father, German. He's funny. He made me laugh in his Naked Episode.
I have a few specific beefs. There's a massive turning point halfway through, but it feels as if half the cast have to turn into idiots to make it happen. Lara is a passive, underwritten character, being defined entirely by her relationship with Leon. (This is particularly regrettable since she's also important and her storyline is an indispensible part of the series, even if I thought it was lazily resolved.) Later there's another, much less prominent, female character who I thought was similarly a bit undercooked in the writing. (They even have similar names. Lara vs. Laura.) In fairness, though, at least the show also has Ema and Octavia and so can't be accused of being locked into paternalistic gender roles.
German's story role in the last third of the series also struck me as a good idea, but not played out as convincingly as it could have been. To be honest, I'm not sure that this is a particularly well-written series.
Oh, and that's a really shallow grave in ep.18. Come on, dig deeper. Well, burial without cremation tends to be prohibited in Japan, so I suppose they might not know if it looks wrong.
Nonetheless, though, there's still quite a lot here to like. It's basically fine. I don't have a problem with it. I probably wouldn't recommend it unless you already like that kind of thing, but there's some meaty material here if you're prepared to dig for it. There's a lot about generations, father vs. son, etc. with the inheritance of the right to be Garo and the very flawed parental figure of German. Leon and German don't have an entirely healthy relationship. There's also some twisted stuff going on with Mendoza and Octavia that hurts to think about, even though the people involved are villainous.
Would I watch the live-action series? Well, it's very popular and successful and I have a friend who's watched it. Also apparently it has lots of boobs. For adults, remember? The anime doesn't, except occasionally on a monstrous demon.
In short, it's okay. You won't be missing that much if you skip it, but it's perfectly watchable and I got through it happily enough. I like the medieval stuff, e.g. the plague doctor outfit in ep.16, which is actually authentic. The plot progression can lurch a bit, so for instance the show's largely static until the halfway point, but even so it's still no worse constructed than your average 26-episode series from a couple of decades ago. I think I probably will watch Season 2, actually.