I'm facing the same decision.
Like you, most of my commute is on main roads, but they are not cleared very often/quickly. I also tend to use a route with less traffic when the conditions are poor... this means side streets that are like a bumpier version of a bobsled track.
For me, If cost were not a factor, I'd go with the 294s. In addition to the extra studs, they are a bit wider than the 160s - possibly a bit better float in the soft stuff. Unfortunately, cost is a factor for me so I'm still undecided. I'm also trying to budget for a disc brake upgrade for this winter.