Thanks for all this. As it happens, when in Plakias I discovered that my goggles were leaking through one lens as the mounting was chipped so I had to ditch them. Even though conventional snorkel tubes may have anti-flooding valves, it can still happen that if you are breathing in and a wave washes over you, you can breathe in a whole load of water and end up coughing and spluttering. Do these new masks protect you from such an experience? If so, and as I don't have a pair of goggles any more, I might be tempted to buy one of the new masks. (Incidentally, the masks I saw being used in Plakias were like the ones shown on the website in shinaria's post.)
Noopsy