I got my SharpSky Pro a couple of weeks ago and have just recently started using it.
The build is excellent and was not difficult to add to the scope. The custom adapter plate supplied was near perfect.
Software installation for the driver was as easy as expected.
I've used it within APT to control the focus. Going from the 0 position (all the way in) to focus took over 130K steps of the motor - it has such fine tuning.
I do have to tweak the settings in APT more to get its autofocus to perform perfectly, but it's been ok so far - the problems are in my configuration of the APT software, certainly not in hardware at all.
I have yet to have a good weather window to do a long session of imaging to see how it goes with holding the focus (it does have temperature compensation if desired). However I am not expecting any issues.
So, if you stumble across this thread because you've got a SharpStar AL-107PH (or some equivalent) and are wanting to motorise the focuser, I can recommend getting the SharpSky Pro unit.