New features on demo: new QuickTime Player interface, screen recording, new AppleScript Editor (tag completion and new formatting), integrated upload to YouTube, and overall spiffy speed. This is on a 3-year-old MacBook, but I did have to use an external drive to get this performance.
Note that QuickTime is both playing the videos and writing them to disk. Framerates and number of videos I can play both go up when I’m not bothering to record.