I installed a Raymarine S1-G (with rate gyro) as a wheelpilot. No complaints. I do not have the rudder reference installed and have zero issues with course / track keeping. I have the rudder ref and will likely install down the line, if only for the tiny predictable increase in accuracy. The rate gyro is the real deal and I highly recommend that option.
In fact, if anyone has an X-5 and wants to swap for the S1G (same unit and interface)...I am looking for an X-5 simply due to the OEM integration of N2k / STng. I would swap for the units, plus some cash.