It's been some time since I've seen the original I have to go back to it again.
Evil Dead 1 was interesting in straight horror approach, and the tree rape scene in my opinion is classic. But it's too straight edge horror.
Evil Dead 2- Was the perfect balanced, Ash had a couple of catchy lines but wasn't a complete goofball, great horror, along with some great humor, and some good action sequences.
Army of Darkness- Good, but not amazing, it's quite flawed, but if your going buy it get the region 3 Director's Cut version the image quality is a 100 times better and features more footage.