Are there benefits for achieving max chaos?

I was playing Dishonored and for now, it seems to encourage stealth. Is there a benefit of going for max chaos? ie. killing anyone I see and making evil choices. Are there unique items? Quests dialogs? Anything at all?

There is actually a significant difference in how a certain character will behave (and how a certain mission could be played) between high chaos, and very high or max chaos (not shown in the ending):

I just finished a 3rd playthrough where I went lethal+stealthy. As a result, I had a moderate number of kills - the first few missions said I had Low chaos, but it had changed to High by the time I got to the last mission, since I went on a bit of a rampage with the assassins. On "very high" chaos, Samuel is a total dick to you and warns guards by firing into the air. On my playthrough, he simply said he was disappointed by how "brutal" I had become, and drove the boat away in silence.

^{Source: Reddit /r/dishonored: "There IS a difference between "high" chaos and "very high" chaos, just not in the ending"}

If you have been extremely violent in your playthrough, Samuel will even fire a gunshot to warn the guards on the isle.

^{Source: http://dishonored.wikia.com/wiki/The_Light_at_the_End#Trivia}

If you play with Very High Chaos and you keep up your bloody sci-fi massacre streak until the end of the game, you'll get a different ending. Check out this thread for details

Well if you consider a darker atmosphere a benefit then yes, but essentially the game will be harder because of increased weepers and more plague rats. A lot of people consider the chaos system a punishment, not a choice.