All of the masks above I have at least tried on a fews times. For the most part, the scores ago are my opinion.
Lens: Thermal or single pane lenses.
Quick Lens: Does the mask have a quick change lens system?
Quick Foam: Does the mask have a quick change foam system?
Size: 1 to 5, 1 being the smallest. There is no metric for this, I just eyeball which is smallest and how it (i4) compare to others.
Flexibility: How pliable is the rubber on the lower skirt/face.
Ventilation: 1 to 5, 1 being the least venation. How well does the mask breath? More holes typical means better ventilation.
Weight: Weight in grams all on the same scale.
Price: Price at release