The Hobson unit was a truly memorable ( for many reasons ) bit of kit. Those who flew the aircraft encountered one side and can thus comment accordingly.
From the engineering perspective, it was a nightmare to remove / install and subsequently rig. There were some serious problems as I recall with the leak rates and the measurement of these rates. The aileron PCU's were not much better either in terms of leaks although for their size and that of the aileron (and aileron response time) they operated, this comes as no real surprise with the work loads induced.
I could be wrong, only ever having worked on Lightnings in a Cat 3 condition, but didn't this also have a Hobson unit fitted, albeit a larger version.