The SIG P220 SAO, SIG P220 Carry SAO and the SIG P220 Compact SAO pistols were guns I desperately wanted to like. I remember my first P220 and thought it would be the ultimate pistol if it were single action only.
The problem is the safety is not in the correct location. It was impossible to shoot with my thumb on the safety. The safety was also a bit narrow and a bit stiff. These two factors resulted in the occasional failure to disengage. The gun and I parted ways after a brief, 500 round affair.
The solution to all this would be to move the ledge down approximately 3/8" and widen it slightly. The grips would have to be relieved.