Even the worst winter tire is much better the best all season/ summer tire. Studies have shown that below 7 celcius winter tire grip exceeds that of the all season/ summer.
The old saying...all season = no season. Also, as some members have already mentioned, SUV/ RWD/ AWD means nothing regarding winter driving ability. The 4 patches of rubber on the ground is what makes your car accelerate, turn, and stop. Don't compromise those 4 small patches.
Changed my tires to winter last weekend, sister-in-law last weekend, and waiting for delivery of wife's winter tires/ wheels (for Merc SUV).
2011 335i X-drive sedan 6MT/ BS/ ZSP/ Chestnut brown leather/ tint 35%/20%, Lux H8 V3