Okay so some people are saying that Jacob has done some good things from what we have seen, but has also done some bad things.
Good: Got Kate out of trouble Gave Jack a candy bar Told Hurley he was blessed Gave Sun and Jin his best wishes for thier marriage.
Bad: Gave sawyer a pen Didn't save Nadias life.
Now honestly every single one of these is neither good or bad. The only thing that is good is what aids the island, haven't we all come to learn that the others aren't bad people? This ties into that. Jacob is good, and so is his enemy: they both love the island... i think.