A green screen gives you the ability to take your surroundings and make it appear that you are somewhere else. Important things you need to know when filming with a greenscreen is to make sure that there are no wrinkles on the greenscreen because it makes it difficult to get the same effect. Another VERY important thing to know is to not wear green clothing. This blends you into the backround and makes you seem invisible. Also grey makes you seem transperent. Problems that can arise from using greenscreen is the edges of your clothes may seem blurry when applying the greenscreen effect. If I had to choose between After Effects and Premiere Pro I'd choose After Effects. It may have been a little more confusing to operate but the results were more satisfying.