I had been smoking for a couple of weeks when I smoked a JFR 6x60.
It made my lips & tongue numb. It gave me the meanest stomach ache & headache ever. I was dry heaving. I thouht i was going to die that night. I swore I would never smoke another cigar again.
I think the Patagas Black are probably the strongest. I've had the JDN Antano (love it), LFD Double Ligero, and most of the rest mentioned and I lean toward the black as the strongest. I enjoy them all. I've also learned to enjoy some less potent sticks too. Stength is ok, but strength with complexity and full flavor is the best.
P.S. I have to mention I haven't had the chisel yet. I only mention it since it was listed multiple times in this thread.