Righto, time to give my opinion.
Here is what I think of Orochimaru-sama.
Firstly, I do NOT think that he sucks and he is by far one of the better characters from the series. He may have selfish reasons behind his actions throughout a lot of the series, but however unintentional it may be, gave many people hope, purpose and a life of some kind. His experiments were very disturbed and inhumane, but he had become obsessed in learning all that he could about jutsu. Who wouldn't do crazy things for an obsession? I know a lot of people would go to any lengths to achieve a lifelong goal.
Secondly, the marks on his face are part of his skin. He was born with them, at least I believe so because he had them from his child-hood and all throughout his adult life. They don't wash off in wet weather, so clearly not make-up. I don't believe they are tattoos, but nobody will really know for sure anyways. The fact that every body he takes over has the markings AND that Kabuto started having the marks on part of his face when he injected himself with the cells leads me to believe that they are birth-marks.
Quick note about Kabuto. His name means "healer" in some language, although I don't recall what that language was at this moment in time. Also, he's not a bad person, just following LOYALLY with whatever Orochimaru-sama wishes. He's probably the only person that the snake sannin can trust and that is a good thing. Orochimaru-sama can sometimes NEVER trust anyone.
Third note on Orochimaru-sama is that he did NOT ruin Sasuke's life. The curse mark was sealed so he had no control over Sasuke. The silly Uchiha boy decided to go of his own free will, BEFORE he was given the pill that fully activated his curse mark. Sasuke CHOSE to leave the village and all his friends behind for power because he's a selfish person.
My final note is that Orochimaru-sama grew up in a war-time situation, with NO family because they were dead before we ever learn anything about him. He grew up alone, suspicious of everyone and he had a twisted view on how things are done. Maybe if Jiraiya and Tsunade and Sarutobi (3rd Hokage) had tried to give him more attention and care then Orochimaru-sama might have never defected from the village or become obsessed in jutsu.
I'd like to also quickly say that ANYONE would be in severe pain if they had a piece of their soul forever sealed, like their ARMS for instance. It is especially bad for Orochimaru-sama, because he devoted his entire existence to learning, creating and mastering all jutsu, so how can he do that without his arms?
Oh, he is not PURE evil either, for he LEFT the Akatsuki and never went back and THEY are the villains of the entire manga/anime after all.
That's my opinion, which DEFENDS the great snake sannin. Care to argue properly against that, or do you think that swearing and insulting are the only ways to debate something?