Pros and Cons of Mounting an Optic on Quadrail?

[noctis]

All handguards are not created equal.

And like Riverine already pointed out the tpial mount are the weakest link for retaining a zero on a rifle that gets bumped and dropped on a daily basis.

[militarymoron]

For the same reasons you cited before? Any others?

yes, same reasons as before. just pesonal preference.