Okay, to start off, when I first read Chainsaw man, I was only able to read up until chapter 5 and then dropped it. It is because of the main protagonist's, Denji's, perverted idealistic character portrayal.
As a female, I never liked shows or overall stories where a character is thirsty to touch some breasts or other perverted things. But after hearing that the anime is coming out this year, I just wanted to give it another go and didn't regret it. Of course, had to suck it up and ignore all the other useless perverted jokes, but it wasn't too hard. The story got really interesting tbh.
At some point, I was thinking that if the story is gonna keep on progressing so well, (referring to great gore, creative take on character designs. The character designs were probably one of the main reasons why I kept on reading the manga, loved to see how much more horrific the devil's are gonna get.

Spoiler, click to view

And it turns out that the most terrifying one of them all was Makima. The girl that looked suspicious, but you didn't want to believe that she would be the bad guy.)

I'll give it a 9 as a review. Then after reading some more and the story going forward I lowered it to an 8 in my mind because the characters were just not memorable and I don't think that there had been any character development whatsoever.

Spoiler, click to view

Power continued to be useless, Denji had some glow ups here and there, but throughout the whole manga he hadn't changed much and I think that he needed the change a lot. Characters like Aki died so suddenly, tho I also think that's a charm of this manga. You're not able to predict what's going to happen next and who's going to die next, but that made me uninterested in all of the characters. I didn't want to get attached to anyone in case they died. Glad it wasn't a problem because, in the end, none of the characters were actually good enough to even like.

Other than that, I was happy with the story even tho sometimes it felt a little rushed or it felt like we were missing a couple of chapters, I was okay with that, at least it was enjoyable. After all that, I finished reading Chainsaw man and the ending was a little disappointing not because of how it ended, but because of how they came to such a conclusion. The ending felt rushed and bare boned, leaving you wanting more (But that's probably a good thing). I heard somewhere that we're gonna get a continuation someday, but still... To end a manga just like that, with so many questions still arising... It just lowered all of my excitement for this manga.
Overall, I enjoyed reading Chainsaw Man a lot. The whole trip of reading it was amazing, and I'm so picky with the manga I read. Plus, it is a quick read. So maybe give it a chance and you'll enjoy it, maybe you don't mind the ending.

Edit: Seems like I pissed off way too many people with my review XD I have my own opinion and this might be surprising to some of you folks.