I feel bad about how often I do this, but I write better reviews when using someone else's comments as a starting point, so I'm going to tackle some of the issues Meins has with Toxic.
The art is simplistic, yes, and in any other setting the heavy shadowing and minimalistic backgrounds with excessive focus on the characters' expressionless features and soulless eyes would have been unsuitable, but in a military setting with such obvious Nazi overtones I found it strangely fitting. The only person in the series whose eyes/face weren't drawn in an odd, frozen way is also the only truly emotional character there, so I felt the mangaka didn't do as bad a job on the art as Meins' comment claims.
As for his accusation of a "deus ex machina ending"... Where? It was pretty obvious from the beginning how/why/by whom the main villain would be killed, and it wasn't difficult to guess who else would become involved in it. It was too rushed of a conclusion, definitely, but I quite appreciated how it was acknowledged - through the words and actions of Loius' father - that just because the Big Bad was killed, all the evils in the world wouldn't magically be righted... Something even much better-plotted works of fiction (and not only manga) have failed to recognise.
That being said, Takahashi Ryo should definitely have used another volume or two to elaborate on the decadence of the Führer's "perfect world," before and after the events of the story. A lot of the emotional oomph was lost due to that deficiency, and unless you're ready - and able - to use your imagination, what could have been a story brimming with feeling comes off as stiff and robotic.
I've noticed some other people comment on the 'gayness,' and feel the need to clarify: there's nothing romantic (at all) or sexual (on-page) between the men in this manga, and if anything, the only ones who give off homosexual vibes are the antagonists (the rapist squad commander, the guy who's apparently head-over-heels for his own brother, the Führer himself), and even in those cases it's strictly plot-relevant. Whether that's a turn-off or not is up to you, but if you dislike shounen-ai and yaoi, there's no real reason to avoid reading Toxic.
Overall: not bad, especially considering its length and the tricky themes it tries to tackle. Not a waste of time, imo, but there's squandered potential galore and it's definitely no masterpiece.