os1 has Attack and Release settings (it calls release "decay")
os2 has full ADSR settings.
when you say "clipping" your terminology is wrong. "clipping" refers to overloud audio which peaks beyond the ceiling of your device. what you hear is "clicking" from placing your chops on a non-zero crosspoint in your audio.
other mpcs have a small default attack which it places overtop sliced samples. it's a very very small fade in/fade out which prevents this clicking noise from occurring. it's like a "forced-zero crosspoint."
jjos wisely removed this to give more independant control to the slicer. to avoid the click, 1 - make sure your slices occur on zero crosspoints. option 2 - don't worry about zero crosspoints, and do this isntead: after slicing samples enter GPE, select WHOLE and adjust the attack for ALL PADS to a very small setting, like 1 or 2. this will get rid of the clicking as well.