First let me just say I was surprised when I saw that there are no reviews for a manga with 65 chapters scanlated (so far). You would think that at least one of those 1000+ members (18 favorites- at this time) that have read Sidooh would sum up a few ideas they had about it and shared with the rest of us by now but, i digress.
The story is pretty straightforward, even though it has it's share of twists, it's plot keeps moving in the same direction; the survival of two teen brothers, in some era of Japan, wouldn't matter if I said the name all you need to know is that the Americans have already started meddling in their business- if you saw "The Last Samurai", I believe that's about the right time frame. That's also how politics is included in the series. There's not enough of it to make the action-hungry shounen fan get turned off by the series, and just the right amount to make things a little bit more interesting.
It's also important to note that Sidooh is not a manga for the lighthearted, there is blood involved, as well as flying limbs, heads and other body parts but, it's no gore-fest either. It starts dark and keeps it that way (I think 6 out of the 9 characters we are introduced to in the first 2 chapters die).
Speaking of characters, this is one thing i think Sidooh pulled off well, not only do the characters have their own distinct personalities but, there's enough of them to keep the plot moving and just the right ammount so you don't start wondering who the hell this guy is and why should I care about him. This also ensures that all of them are fairly well developed and we actually get to understand their personalities.
Character design is also pretty well done, very samurai-ish and very fitting to the manga as a whole.
The art is one thing that may put off some readers. It's either love it or hate it as far as I see it. If you have read any of the other Tsutomu Takahash's mangas, you will certainly notice his unique style emerge in Sidooh. For me, at least, it's a breath of fresh air to see actual semi-realistic humans that don't seem to come from a long line of models and that actually have distinctive characteristics.
Overall I must admit that Sidooh is a great ride, and i found myself getting drawn into the story quite a few times (the kind of thing where if someone were to offer you a bag of money you would keep your head turned to your laptop with a hypnotized stare and say -yea one minute). That is not to say it's perfect, it surely has it's flaws both art and story-wise. It's just not your typical shounen or samurai manga and that is by all means a good thing.