Cowboy, because the Speer Gold Dot is overwhelmingly the most popular choice among agencies carrying .357 SIG, it has built the biggest data base, and because of that and the sterling reputation developed among those agencies, it gets my "first choice."
I've only run across one reliably-verified shooting with the 125 grain Remington Bonded Golden Saber in .357 SIG, and in that case it performed superbly. Out of a short barrel Glock 33, no less. It seems to run neck and neck with the Gold Dot in simulated media testing. It's also very accurate. In a Glock 31 I carry often, the Gold Dot gives me an inch and a half at 25 yards, but the Golden Saber gives me an inch and a quarter (5-shot measurements center to center in both cases.) Both are extremely reliable.
I would be perfectly comfortable carrying the Bonded Golden Saber 125 grain .357 SIG load.