It's actually a 9.5/10 for me. The series is masterpiece, no doubt. The series is really unique on its own. It is definitely one of the best and most unique suspense crime thriller with a supernatural twist to it. And then the philosophical concepts in the series made it even better with also slight touches of humor, action, and cheesy romance. At no point I felt that the manga was boring at all. I was hooked to it through out. Has some really memorable characters, each character in the series has been given an appropriate amount of personality, attention and screen time. The art really works well with the story. The series does has some minor flaws but when it comes to the good stuff then I must say that there is 100 times more good stuff than the bad stuff hence, this series is a masterpiece.
My Scores:-
Story: 10
Art: 8.5
Character: 9
Enjoyment: 9.5
Overall: 9.5


My Flaws (Spoiler Alert!):-

1. At very few places I felt that the way L or Near, when they were trying to figure out Light's plans, it felt like they were only able to so because 'the plot requires it'. E.g. : The assumption by L that a second Kira exists could have been written in a way where first he feels like Kira is acting odd and then later on could have made a guess that maybe a second Kira exists but in the manga he firsts says that a second Kira exists and then when he gives the reasoning which feels like it was as because the plot required so. (Please read/reread that part yourself to really understand what I mean :-) )
Otherwise I was very convinced by the ways L and Near used their minds to decipher the Light's plans.

2. There were no cameras in the Yotsuba building in my opinion was stupid. Like which big company does not need security? I would have been more convinced if Wedy (the girl responsible for breaking trough the security/surveillance could have just said that she was able to breakthrough the security systems instead of saying that there was no security/surveillance at all.

3. I felt that there was a need of a chapter after every major arc of the manga which would have shown us the aftermath of the previous arc. Especially after L's death. As he dies, we are straight away given a glimpse of Near which then steals away the feeling that whether now Light will finally be able to rule the world or not. I think they should have shown him after or at the end of the chapter after L's death in which we would been shown the aftermath of L's death and how the situations are. Sure we are shown the time-skip and that how after 3 years of L's death there has been an increase in Kira supporters but then because we were shown Near earlier, it stole the feeling of suspense and also kinda gives us a bore effect that straight away we are back into a big arc. A light story arc is kinda necessary when it comes to series where the plots are very heavy as to give us a smooth transition towards the next arc. This kinda also puts less pressure on the audience while they are watching/reading.

4. Mello's character design was kinda too feminine. It really made me confused while reading the manga. At first glance I was sure that it was a female but then I saw that the characters were referencing Mello as 'he, his , him' , that is when I realized that Mello was a male. I dont find in anyway necessary for Mello to have a feminine look.

5. Light is not shown interacting with his family after his father died, which in my opinion was necessary as his family played a very big role in the first half of the series and even before his father's death. The writer should have shown a little interaction within the family members as to what happens to them after Light's father dies except for that one phone call which was shown around Christmas /new-year (not sure which one of the both was it).

6. After Rem dies, the ownerships of the death notes keeps changing which kinda confuses us. I had to rewind myself with almost the whole story in my mind to finally figure out the ownerships of the Death Notes at certain points in the story. It would have been better in my opinion if they would have atleast given a proper explanation about the ownership and whether how even after losing a certain notebook Light will not lose his memories. This explanation should have been given especially after Light's father's death.

7. Near's character was needed to be more interesting and needed to have more of his own personality. I did not like the fact that he was too much like L, even though he was his heir, in m opinion he still should have had his own unique personality and this is the reason many people don't find the second half of the series as interesting as the first half because first of all, we get a repetition of one vs one stuff and then even that with a less interesting character, it kinda can then give little bore effect. In my opinion both halves were very interesting but it was just that they were slightly different from each other. Like the first half of the series is a little more fast paced than the second half. But slower pacing does not necessary means that the the particular story-line is boring/not-interesting. I think the problem was Near's character. Only if his character was a little more unique and interesting then even after that little slow pacing, people would have equally enjoyed the second half as the first half. I personally enjoyed both halves equally as I was aware as to why some people found it not interesting and so it was easier for me to just forget about the problem with Near's personality and keep enjoying it. Though there were some unique aspects that I loved about Near too but as he was such an important character to the plot and that the writer decided to repeat the one vs one concept, it was necessary for him to be a little more unique and interesting.

I cannot write the good stuff of the series because the series juts has too many good things in it. This series no doubt a must read for all.