There are a lot of good freediving masks out there, but they all have good points and challenges.
The Sphera was the mask of choice when I was taking my PFI Intermediate Freediving course. All the instructors used them. They have very little volume to fill when you need to equalize, are flexible so they don't hurt as much before you do equalize, it fits a lot of face sizes, and they're very streamlined. But as they said in the course, they're a consumable product. In other words, one will probably last a season. The plastic lenses scratch very easily. They also have some distortion at the curve of the lens. The other classic freedive specific masks are the Cressi Minima and Spetton Falcon. These also are very low volume and have plastic lenses, but are not as flexible. They both tend to fit smaller faces best. All three of these masks are basicly swimming goggles with a nose pocket.
There are lots of masks designed for spearfishing as well as freediving. The classics here are the Cressi Superocchio and Sporasub Samurai. These fit more medium sized faces and have glass lenses. They have a little more volume, but still a fraction of most scuba masks. Omer and Riffe have a wide selection of different masks designed for spearfishing that fit a variety of faces.
All this being said, before I buy a mask I want to try it on. I've tried a few of these, but not all. I first tried the Superocchio and Samurai. The wide bridge of my nose wouldn't work for these. I needed a little bigger mask. Because I have prescription lenses in my mask I didn't think I wanted a mask with plastic lenses, and certainly not one that was flexible. I finally got to try on a Sphera and it did fit very well. I'm thinking of buying one and squinting a little.
Hope this helps.
Jon
