You really don't want a slip clutch if you can help it. If you are continuously whacking things that could rip your drive line apart then yes. However for most of us the occasional unsuspected "whack" is what we experience. Reason for my answer is 37 years of Farming 101 at Hard Knocks U. Most cutters sit out in the weather. The slip clutch has to slip to function. If frozen due to rust or bolts over tightened it can's slip. If bolts are not tightened enough it slips trying to cut normal foliage.
A shear bolt on the other hand, Grade 2 works best with a locking (nylon insert ok) nut, with a tad of slop at the coupling interface....they last longer for me if a little loose.....reason for the locking nut. Just carry a couple of spares with you in addition to a punch, small hammer (or suitable substitute) and a couple of wrenches to fit.