I like the straight cut myself but, that being said, I was at a B&M recently and bought a chisel-shaped cigar. The owner asked me if I knew how to cut it. (I told him I was still new to this, so it was a welcomed question, not offensive). I told him I had assumed a straight cut but he told me to punch it not on the tip but on the side of the chisel and then point the hole downward.
Haven't tried it yet, but I will.