As Sharbotcom noted, all-seasons are too hard in cold weather to be effective. Once the regular daytime temp remains below 7C or 45F they are no longer soft enough to provide good traction and handling. Winter tires are not just for traction but also for superior braking and cornering. These benefits are not available with any type of all-season tire.
The X-drive will help with acceleration but it doesn't help with braking, especially in slushy, slippery conditions.
Go with winter tires and enjoy your car to its potential.
Remember the most important part of winter driving is the person behind the wheel.
2012 BMW 535i X-drive; Space Grey/Black Dakota, Fineline; Executive (Auto trunk, NAV, HiFi Prof, Lumbar, Rear Cam, SIRIUS, Voice), Technology (Blind Spot, Hi-Beam Assist, Lane Departure, Surround View), APPS, Rear heated seats, Tint.
Retired: 78 300D, 81 300SD, 87 190E, 88 Porsche 924, 89 260E, 93 300E, 97 Volvo 850, 98 E320, 03 BMW 325iT, 02 C230 Sport Coupe, 08 BMW 535i
Last edited by Gilgorm; 11-14-2012 at 12:12 PM.