I like FoCal very much. It has helped me with various cameras and lenses.
Yesterday I made some pics with my 50/1.4 on a 6D body (before adjustment) and they were not sharp. Today I ran that body and lens through FoCal and discovered that the lens needed a +17 adjustment. What a difference! It's like having a new lens.
However, FoCal is still in development and seems a bit unstable. I've had it shut down unexpectedly a number of times. Also, it is supposed to support the 6D but I could not get it to work in the fully automatic mode without forcing the Manual Settings Change (MSC). Before I set it to MSC, FoCal would run through the whole test automatically, but it seems it wasn't actually adjusting the AFMA setting. The analysis graph showed pretty much the same results from -20 to +20, which made no sense at all. After setting it to MSC, I ran through the automatic test but with manual AFMA adjustments and the graph showed the proper curve with a peak around +17. It took some effort, but now I have a good result and it really makes a difference in the pics.
That said, I do wish that Canon would update the old design of the 50/1.4 to one that is more precise & consistent in focusing. The older designs seem to be the least consistent.