I've used both for years. IMHO the HKS is tougher with less moving parts while the Safariland is quicker for me even when loaded with semiwadcutters.

As I type this there is a Safariland Comp I in my pocket loaded with .45 Colt for my Redhawk. But I'd be just as comfortable with an HKS. Kind of a Ford vs Chevy thing...