It's the only Blade of the Immortal adaptation to date to do the whole manga, from start to finish. It's complete, whereas the 2008 anime and 2017 movie don't even pretend to cover it all. It's a strong, stylish show that I basically admire... but it has two big problems.
This show's most memorable aspect is its gross-outs. It's visceral. Its fight scenes aren't beautiful, but instead people getting hacked to bits. That I like, but the sexual violence can be hard to take. (Theoretically, that's just faithful to the original, but it's different when brought alive in max-gross animation. One of Tomoko's best friends in Japan is female and a fan of the original manga.) Paradoxically, even more horrific things happen that one accepts as a legitimate direction for the story, e.g. the medical experiments on an immortal. Those were nuclear-level disgusting... but I was fine with them. Habaki's a bastard. That story arc's asking questions with interesting answers.
The sexual stuff, though, is sick and uncomfortable to sit through. Shira repeatedly commits worse-than-rapes, while there's also a sexual torture scene. Yes, I'm sure all this really happened to women in this historical era, but it's still disturbing to see it repeatedly in something created for entertainment.
The show's other problem is its last half-dozen episodes. Having run out of dramatic steam, it's just lots of fights, often against someone exotic whom we've never seen before. (There had been other slow patches, e.g. towards the end of the first half, but messing up an ending is a special kind of failure.) The ep.24 postscript does nothing for me either.
Those are major problems, but the show's also getting a lot of things right. When it's on form, it's one of the best things I've seen in its genre. As with Miike's film (but in a different way), I enjoy its rough edge. It's a 24-episode samurai epic that didn't bore me. The fights are crude and brutal, while the stylisation can be bold almost to the point of abstraction. Meanwhile, Manji's voiced by the great Kenjiro Tsuda, while the show's portrayal of Rin is strong. (Ironically, I think Manji ends up being underused. They don't really examine him in the show's second half.)
Half of this show is extremely strong, but the other half makes me say "read the manga". Apart from anything else, 24 episodes vs. 30 manga volumes meant a lot of ground to cover and apparently the anime's trimmed a lot of characterisation. I bet the manga's version of the last quarter puts more flesh on the bones of all those fighters we've never seen before, for instance. (In most anime, one manga volume is two or three episodes.)
Is the show worth a watch? Yes, if you've got a strong stomach and/or a fast-forward button. Is it worth a rewatch? Possibly, yes. There's quite a lot of depth, with even the most loathsome characters (Habaki) being honourable while the fan-favourite Anotsu is a semi-nihilist who's assembled a group of murderers to honour the memory of his scumbag grandfather. (I think Anotsu is even aware of the contradiction in this. He just doesn't care.)
That said, though, after two anime series and one movie, I've had more than enough of this story. Goodbye, Blade of the Immortal. I could imagine rewatching Miike's movie. The two anime, no.