It's kinda action-packed and lots of details are thrown into the writing for certain intrigue. I can't vouch for the accuracy of the writing but well, it's very common for action manga to throw in all sorts of names, even if the functions of said groups and organisations diverge from reality. Still, it's fun to read. A shame the story was ended just like that.
Btw, this manga is as realistic as most of those action movies and books are, haha. There's no way conspiracies, evil organisations, justice enforcers, mercenaries, paramilitary groups, etc. could exist in such abundance. And yep, it's probably as realistic about America, as most Hollywood movies are about Asia or even about America(especially when Southern people sound more like total rednecks or savages).
The characterisation is just okay... it's not always that consistent, I guess but it's decent enough for me. The characters are rather emotional and the plot has a very Asian soap-opera feel. Many of the dramatic moments remind me of their tendency to rack up the drama and toy with the viewers' emotions, in order to leave a strong impression. Some probably dislike it though and see such writing as "cheap". And as for Eric's guilt about the usage of weaponry, I found it quite realistic 'cos I know an engineer who creates bullets, guns and other sort of weaponry and machines for the military. She was filled with lots of guilt when she saw her own creations being used on the battlefield and it took a long while for that guilt to surface. Yet as a researcher and engineer, she still continues for her interest in science. Same for many of her colleagues.
I did wish the characters were a bit more masculine but oh well.