If you need the best quality and performance, you need to set your screen to the native resolution of the AppleTV 2 (1280x720) or AppleTV 3 (1920x1080). This will eliminate scaling and other artifacts. The preferences for AirParrot will allow you to find the best trade off between speed and quality of video. The closer your AppleTV and Mac are to your Wi-Fi access point, the lower the latency and the better the quality of video you'll see!