What are the key differences between a fixed base and plunge router, and how do these differences impact their functionality and versatility in woodworking projects?

A fixed base router is stationary and the bit depth is set before use, making it more stable for precise cuts. A plunge router allows the bit to be lowered into the material during operation, offering more flexibility for different depths and angles. The fixed base router is better for straight cuts and edges, while the plunge router is more versatile for intricate designs and patterns.