Wuthering Heights

I saw a beautiful adaptation this week of Wuthering Heights by Emily Bronte. I thought it was very well done, except for the last half where Heathcliff seemed to have lost all redeemable qualities. I haven't read the book and there are too many books I want to read, so I figure that is one I probably won't get to in this life. If any of you have read it, would you let me know if he Heathcliff actually turns evil, or if he just wasn't played right? I really want to like him, but I am struggling...