Bloody Monday tried to be a suspense-thriller anime which involves a lot of "black hat hacking". Although they try very hard to use accurate terms, anything involving computer crimes tends to be misunderstood by traditional storytellers, and that is still the case here.
Lots of things are almost accurate, and for that reason, I got sort of annoyed with the series.
Another annoying thing was that the "experts" often make the same novice mistakes, over and over again. This might be accurate if they were run of the mill government workers, but, they're supposed to be elite, highly trained specialists.
On the other hand, they are lots of twists in the plot, and it kept me wanting to know what would happen next.
This story would do well as a anime, especially if it was stretched out more to fill in the minor characters (and even major characters) more, e.g. like how True Blood was adapted from book to tv show form, and minor characters were "fleshed out" more, in the same way, the limits of the manga format mean that a lot of characters don't get much attention here.
It might sound like I hate the series, but, comparing it to others, like, say, Liar Game, Death Note, and Hunter X Hunter, I have to say that it feels a bit rushed and lopsided.
So overall, I give it 7/10... but, due to the suspense aspects, whilst reading it, esp. if you read it one volume or a few chapters at a time, the story is told well enough to keep you interested, which is why I rate it 9/10 for enjoyment.
The Art, I don't know what to say... it seems good, but it's manga, and for black and white drawings, they're all mostly the same to me, I don't pay attention much to the art quality.
The Story, because of the suspense and trying to be accurate, I'd rate it 8/10... but after reading Owning the Box and such, I really think you can't half-do accuracy like how everyone else does, but I realize that only the geekiest of geeks will care or even see the problems.
And so, overall, I'd recommend it, but, as a parallel to a "thriller" movie. If you like plot twists, suspense, and exaggerated heroes, then you'll like this.... but it isn't the great work that it could have been, if more care towards realism had been taken.