Hi Colin,
Automated focus certainly has helped me to collect better quality data. In the past, I would manually readjust focus maybe once or twice a night, but it was not until I got automated focusing sorted that I realised the degree of focus shift with temperature change. Also, with manual focusing, I would need to slew to a bright star, refocus, go back to the target...time consuming and quite labour intensive.
I have been using Moonlite with stepper motor combined with SGP for a few months and have found it to be very reliable and all works very well. I set it to refocus with every one degree change of ambient temperature and SGP very finely and accurately readjusts focus. I also recently added automatic rotator (also from Moonlite) and the whole package works extremely well - no slop/tilt due to gravity at all (have QSI and SX filter wheel and OAG attached to the focuser). In my set-up, both focuser and rotator are controlled via SGP. SGP ensures everything goes smoothly and now I do not need to "intervene" during imaging session or waste time refocusing and slewing around the sky. In sum, while not cheap, Moonlite has been one of my top upgrades and it turned my rather average TS doublet into a neat imaging machine
