The HelioRC Spring flight controller is the only one specifically designed for use with ButterFlight. It has an F4 main processor with an F3 co-processor specifically for gyro data filtering. This means that it's the only current Betaflight-like flight controller that can run at 32 kHz gyro sampling AND 32 kHz PID loop rate... without any overclocking.
But?
Is it actually any good?
Today we're going to fly it and see how it handles this quad.