Dry snorkels sound excellent, and generally are, but kow about the position of the snorkel tube.
When you are swimming along -
head down - your snorkel tube is straight up
- at 12 o'clock.
But, when you come up from a dive,
head up, your snorkel tube is level with the water - (3 o'clock). or
If you put your mouth slightly up,
the tube can be pointing slightly downwards - (4 o'clock') with the valve beneath the surface.
So, you try to draw a breathe in and
the upper valve is closed
and you panic a bit.
The snorkel is doing exactly what it is meant to.
As long as you understand what is happening,
dry snorkels work very well.
Oceanic Ultradry is the one I use
but there is quite a range now
so ask your dive shop.