I haven't snorkelled much and bought this and a yellow one for my wife for a trip.
I read some good reviews and thought that it would be fine. when I tried it I had a problem with it letting in water, my wife's one seemed a bit better. I actually ended up using it for scuba diving down to about 10m.
to cut a long story short, it turns out that it works fine if you position it correctly, I only found this out after the scuba experience, there's some secret to this and to be honest I've forgotten it, but I like the product and will experiment in a swimming pool before my next trip.