I has both. I've used both in situations that might be declared as "deep winter" - ie very cold/snowy.
The deep winter collar stretched out a little bit after a while and the gap between the two "sections" became a channel for cold to get in. In addition, if you use it to cover your face and ride hard breathing heavily into it, it gets a bit damp and soggy when you take it off your face it becomes a cold and unpleasant spit towel.
Now I only really use the DW collar when I can't find my regular one or if the regular one is in the laundry.
EDIT - quoted wrong bit...
I has both. I've used both in situations that might be declared as "deep winter" - ie very cold/snowy.
The deep winter collar stretched out a little bit after a while and the gap between the two "sections" became a channel for cold to get in. In addition, if you use it to cover your face and ride hard breathing heavily into it, it gets a bit damp and soggy when you take it off your face it becomes a cold and unpleasant spit towel.
Now I only really use the DW collar when I can't find my regular one or if the regular one is in the laundry.