The X3 handles great in the snow (I know, I owned one and have routinely driven it in snow exceeding 10 inches on a regular basis).
But its not like its that much greater than any other well equipped SUV. For example, as good as the X3 is, my 2007 Toyota 4Runner was much more capable in the deep stuff.
Many, many cars have AWD/4WD systems, and while BMW makes one of the best, many of these other systems are extremely capable (i.e. Audi Quattro) etc...
Midsize and larger trucks like Tahoes, Pathfinders, 4Runners, Land Rovers etc are virtually unstoppable in the snow...
Everyone on here loves to say, I saw a [insert your SUV of choice] in the ditch, and I happily drove right by in my superior little BMW X3.
Well, the X3 does have a great AWD system, handling and balance, but don't kid yourself, its not THAT much better (and is sometimes worse) than a very capable 4WD Tahoe with much higher ground clearance, locking differentials, etc. etc. Most of those very capable 4WD vehicles in the ditch are there because of driver error, not because of a lack of capability. And in some cases, you can DRIVE a Tahoe/4Runner etc. OUT OF the ditch, whereas you can't necessarily do that in an X3
All of these vehicles become the same on ice...its just annoying how X3 drivers think they are special and immune, or that their cute utes are that much better in the snow then say, a Tahoe, 4Runner etc etc