Yes the X drive system is very advanced. We had moderate snow, about 3 inches. I have a 4.8is, with the stock 20" rims, and conti DWS all season tires. I was ripping through all the snow I could get into without a problem. The car almost doesn't want to acknowledge the fact that there is snow on the ground. Even drifting through snow, full throttle, the car pulls through and straightens up.

Now if you were to slap on some dedicated snow tires and thin rims, I am sure it would be absolutely insane in the snow.

My current setup is so great, that I am waiting for some heavy snow to decide if I am going to keep or sell my winter wheel-tire combo.

Go on youtube, there are a lot of x5 vids from Russia where you can see the capability of the X in the snow.

Here are a couple.
This one the guy is trying to get out on the sidewalk as the street is not plowed, which is common over there. He plows the sidewalk with the X.
http://www.youtube.com/watch?v=4ujac...eature=related

Compact ice/snow on 20"
BMW X5 4.8 IS in LITHUANIA - YouTube

Pirelli Scorpion tires
BMW X5 E53 (X5M) 4.8is

And one for you. How's this hill compare for you.
X5 - YouTube

Honestly, I have never seen an X5 back in Russia get stuck in snow. Well unless the person was a retard, with shitty tires, summer tires, or flooring it like a retard. But those are the people that will get yelled at by everyone they know, and it won't happen again.