Note: This review covers the entire series and not just Vol. 1. Minor spoilers are included.
After re-reading Vol. 1-6 before moving onto the final two volumes, I finally managed to finish reading the NHK manga just now. My feelings are pretty mixed about it... I enjoyed reading it a lot but, at the same time, I was often thinking that there was way too much needless content included - far more than in any other version of the NHK story. Because the huge amount of needless content, my enjoyment levels dropped quite a lot after the first two volumes. If only for the fantastic art I can't score it lower than 8/10, though.
Vol. 8 was by far the most disappointing volume in the entire series. It all seemed so pointless and, in comparison to the earlier volumes, it was far less entertaining. There was lots of chatter included yet I never really cared about what was being said, or even followed a lot of it. The story just never went anywhere in the final volume, instead going around in circles as Misaki pushed forward with her love contract, Satou went along with it because he had nothing else and Yamazaki rambled incomprehensibly about starting a revolution. All I saw was the difficult to follow conversations of not-so-sane people that were put in to extend the story to 40 chapters.
While I'm still covering the negatives, I'll also say that I wasn't best pleased with how the original story was changed in order for NHK to become an eight volume manga. There were lots of small (but important) changes that were made in the manga version, some of which seemed to have been made as the manga was on-going, an example of which being how Satou first said he wasn't a virgin (in the novel and anime he slept with his senpai whilst still at school) and then later said he was. The most bothersome change was how, in the manga, Misaki only lied about having a bad childhood - it made her difficult to like character into an even more hard to like character. Too many changes were made in order to extend the length of a fairly short story.
On the flipside, I liked the first two chapters of volume 7 a lot. The events that took place in those chapters never occured in either the novel or anime, and they were only able to work so well because Satou was still a virgin in the manga. Kashiwa's easily my favourite character in NHK, and the so near yet so far romance between Satou and her is the most emotional part of the NHK story for me, so a few chapters that gave the pair more time together were very welcome additions. It was nice to see Satou confess his feelings in this version of the story...even if he later went back on what he said because he didn't have what it would've took for him to take his relationship with her onto the next level.
I don't like how open ended every aspect of the NHK story is, but I've always found the relationship between Satou and his senpai (Kashiwa) to be touching. I actually came close to crying during episode 14 of the anime simply because Satou let her go. The reader/viewer fully understands why Satou doesn't do what his heart tells him to with her, but it's always hard to watch when you know the two could've been happy together. If only Satou had had the balls to put his arm around her when she was crying way back when he wasn't a recluse and she wasn't a married woman - his future might have turned out slightly happier. What makes the whole thing even more agonizing is the fact that Satou is a better match for her than her the guy she ended up marrying...
Anyway, to sum it up, my thoughts are that, although still very good, the manga version of the story is the weakest of the three versions of the NHK story. It has some nice additions to the story but the majority of the new content doesn't actually add anything. We didn't need to see Satou spend time at his parents, coming up with masturbation plans whilst he was supposed to be finding work, and we also didn't need to see Satou spend some time wondering around homeless. The novel was a bit too short, the anime got the length just right and the manga dragged on for too long. I don't feel bad about spending over £40 on the manga but I do feel I should've spent the money on buying the anime instead.