It seemed like you used the same DM for both of those 3D presets...
Uhh as for the winter one, you should change up the scope so it doesn't pile up on the edges. When you use those sines with the random numbers you get more snow flakes on the edges. try something line rand(200)/100-1
The presets are quite ok. The dm in the snow preset could do with some good alpha blending code, to hide the uglyness. The 3 ssc's in the 3 presets could be combined into 1 ssc using some quite easy if() statements. You can create more interesting stuff too.