Hi Kasia,
I've had a VSB opener for a couple of years now, and yes, I have had problems with snow and ice!
I had it mounted on the inside of the coop, with the external light sensor stuck through a hole in the wall, just underneath the 'eaves'. This bit worked fine - the electronics were kept nice and dry, and the sensor never got covered in snow.
What I think may have killed it was ice forming overnight in the slidy track of the pop-hole. Basically if the door jams before it's all the way up, the motor will keep on trying. The symptoms for me were that the (new) batteries were completely flat, and although the motor still worked, the electronic controller was dead. Importantly, the unit was replaced by the manufacturers under warranty without quibble (it was only later I made the connection with the icing up).
To solve this, I've now put a three-sided 'porch' around the pop-hole. This keeps all the wet and snow off it, and I've had no further problems. Likewise, if you install your system with some careful thought, I'm sure you'll be fine too
.