A slipped hammer should also be caught by the safety notch on a non-rebounding hammer as long as the trigger isn't pulled. Generally speaking though these are more fragile & prone to breakage than are the rebounders.
I really prefer hammerless but have used many hammer guns over the years with no problems. With my small hands though I never attempt to cock Two at a Time as for a double.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra