The dichotomy of "Skin of Evil" is that there are some boring, poorly written parts and then there are some jaw dropping, incredibly dramatic moments as well. It's certainly a must see for a Star Trek fan, but most of the episode isn't all that good. The problem is two-fold. Firstly, the premise of the story is weak and not something that could ever hold a viewer's attention for more than 15 minutes. Second, there are big budget problems; most of the episode takes place on the first season's fake looking planet set, and there are a lot of repeated shots to save money. There's also a lot of talk. Troi talks to the creature. Picard talks to the creature. The creature talks to them. The creature talks to himself. Troi talks to Picard. Picard talks to his crew. Tasha Yar ends the episode by talking to everyone. If you like talk, this one's for you! Still, this is a must see for Star Trek fans for its historical significance, and the last scene is wonderful.