For what it's worth, I use SGP for focusing both my Takahashi FSQ 106ED, and my Edge 9.25 at f10 2350mm. On both scopes I get beautiful repeatable v curves and crisp focus. Temperature compensation ensures I can go hours without rechecking focus. Donuts have become a non - issue with the latest focusing routine. One of the greatest things about SGP's focus routine is that I don't have to leave the target. That is a huge convenience and time saver to me. I can't imagine the improvement that some other focusing software would have to offer to make me be willing to leave the target every time I wanted to check focus. The only improvement that I would be happy to see would be the image download speed of SGP in general.
Dean