Takeaways:

• Color Key provides more blocky, preferred output than Ultra Key
• Ultra Key provides much more customization than Color Key
• Scenes with fewer colors are probably preferable to very colorful ones like the highway clip used here
• Lower-definition source clips may provide more aesthetically-pleasing, blocky masks
• Beware over-tuning. Glitchy randomness usually comes from broad strokes and coarse settings changes, and extensive tweaking can lead to decreasing/inverse returns.