I just helped a friend install the x-5 on his Benetau 35s5. Installation was a breeze, really no different than the S-1 except the omission of the rudder sensor.
The real test of any wheel pilot is it's ability to hold course in a following sea. We took his boat out in 20-25 knot winds and 4-5 foot following seas. the x-5 held the boat every bit as well as my older s-1 system with linear drive and rudder sensor. I was really impressed with the "learn" function of the course computer. The first few yaws were a little excess, but the computer kicked in the on each succesive yaw, and the steering was more precise as we went.
I am seriously considering buying the upgrade to my s-1 course computer to include the yaw sensors. They really work.
The X-5 wheelpilot is definetly an improvement over the S-1 and the installation is easier and cost as low.