Yes, it's like Death Note….except it's incredibly awesome until the end.
20th Century Boys is my favorite manga and Kanna is a very good lead character.
Naoki Urasawa is an amazing story teller and the story continues to take unexpected twists until the very end. I liked 20th CB even better than Monster and Pluto.
20th CB would NOT have worked had the lead characters not switched...I mean the whole story was kind of dependant on that event.
I just finished it this past December and was amazed at just how good it was. Until that, One piece was entirely my favorite manga without any others even close...but now it's at the very least tied with 20th CB for my favorite. That's how good a manga it is.
The characters are deep and well developed, the story is very unpredictable. The "halfway" point that has been mentioned is volume 5 / 24...and at that point you really know so little of what's actually going on, I hardly see that as a point where the story drops off...on the contrary, that's where stuff just begins to heat up.
My only complaint with the series
SPOILERS FOR THOSE WHO HAVE YET TO READ THE MANGA!!!!!!!!! (HIGHLIGHT)
is that in the end, I would've liked to see a real conversation between Kenji and Kanna….especially given the comment about her being a disappointment. I'm sure it was only in regards to her actions in the last part of the story, but it still would've been nice to see the reunited uncle and niece finally speak to eachother. I also would've liked to see what happened with Kenji and Yukiji. I mean, Yukiji wasn't at the UN, so I suppose she was on tour with Kenji as only she, Kenji, and Otcho failed to appear and we know where both Kenji and Otcho were.
END OF SPOILERS!!!!!!!!!!!!!!!!!!!!!!!!!
So YES, read 20th Century Boys! =D