Which statement is true regarding proportional valves compared to servo valves?

Proportional valves are indeed generally regarded as more rugged than servo valves. This durability comes from their simpler design and construction, which typically incorporates fewer moving parts and does not require the precision components that servo valves do. This makes proportional valves better suited for applications where they may experience harsh operating environments or fluctuating conditions.

While proportional valves do play an essential role in controlling fluid flow and pressure, they do not outperform servo valves in terms of accuracy. Servo valves are specifically designed to provide high precision and rapid response, making them ideal for applications requiring fine control. Additionally, they are typically used in systems needing lower particulate contamination, which means they require less restrictive filtration compared to the more rugged proportional valves.

In summary, the characteristic that makes the statement true is the ruggedness of proportional valves relative to servo valves, as they are built for durability and can withstand more challenging conditions without compromising performance.