I don't know about the manga, but in an earlier episode of the anime there is this serial killer that ends up going to hell as opposed to soul society due to having done horrible deeds. In the first episode Rukia explains to a soul about how wonderful soul society is.
When you think about it, it's a bit strange because it makes you wonder how there can be so many bad parts of soul society if all the evil souls end up going to Hell. It also makes me wonder what to part of soul society each soul goes. Is it just random or what?
It's not terribly strange. Not only was that particular killer just a total sadist, by killing people like that he probably created several Hollows by murdering the people he murdered(which I'm sure caused them to despair immensely).
If that logic is indeed accurate, then only irredeemably corrupt or wicked souls would be sent to Hell, while those that are at worst neither good nor bad with personal flaws wouldn't deserve an eternity of punishment.