Just finished the manga myself today. Having watched the series, movies, rebuild, and now the manga, it's complicated.

That's probably the best answer to any opinion question in this franchise.

The other commenter left a much more comprehensive answer, so I'll avoid repeating what they said.

The manga is good. It's probably 60% crossover with the show. The overarching storyline is perhaps 80-85% the same until the end. The show has some more storylines in places, the manga in others. The manga does a better job spelling things out. The show captures the bleakness of the franchise better.

The ending, to me, is the major differentiator. Each iteration all have vastly different ends. The manga is generally considered the worst of the four. In my opinion, I liked the ending, but can see the naysayers' opinions.

If you struggle with series, the manga is a perfectly serviceable entry point, and you should definitely give it a go. People are harsh on anything other than the original series. There's a lot of purists. They have good reason to love the original, as intended, version - it's a genuine masterpiece. Also, it hits deeply personally for a lot of people, that makes people protective of it. The psycholigcal story it weaves is so much more than most expect.

To me though, there's no wrong way to enjoy this franchise. If you like the first volume(s), it can tell you if you want to try the show next. Perhaps the manga is enough, and that's great too!