Someone mentioned early on in EW that melding an gearing tenacity was around 8% less damage taken. As a low end content player, that seemed like a significant amount and I have geared that way ever since.

Has it ever helped me? No idea

Would DPS Materia have ever helped me get faster clears? Very likely not in PUGS

Would be nice to see the difference of Direct hit to Tenacity in the main post. Best case senario and all. Just so us less HC players could see what the big difference is.