Aware this is an old thread but just to weigh in on the current state of the full face snorkel market as I recently went through the research process for my family.

The risks associated with these still exist, namely they don't work well for exercise, and almost all of them don't allow for equalisation. However the materials used and face seal are improving. Some also are now produced with flat lenses which reduce the distortion caused by the rounded variety.

I found the below article helpful in my research (I ordered mine in Australia).
https://theadventurelab.com.au/diving-snorkelling/best-full-face-snorkelling-masks/