If you're on relatively flat land RWD will work ok in the snow with the right tires. But, IMHO, RWD doesn't work for crap in the snow if you have any steep grades to climb. I don't care how much fancy gee-whiz electronics you put on it, if the rear wheels are trying to drive a (heavy) front engined vehicle up a steep grade you're SOL.
I actually hated the traction control on my FWD VW Passat in the snow. Just when you built up some momentum it would cut in and slow you down. I don't know exactly how it worked, and if there are a lot of different systems, but the one on the VW seemed to simply brake the wheel that was spinning faster than the other. It did not send more power to the wheel with traction. It felt kind of sickening too when it kicked in, like something was wrong with the car.