The Dye I4's were my first real investment into paintball. Im only like 5' 5'' no naturally have a small build and head, so this mask fit me really well, the strap is comfy and fits snug even when diving over beams in snakes
Ive also worn Grillz before, though I havnt owned a pair so didnt get a decent chance to review them fully, both very comfortable, field of vision was slightly better in the i4's, and I find the lenses much easier to change over.
But as I stated before I havnt owned a pair of grillz so can't give u a full opinion.
Regards.
BM