I's not so terrible. We did it in March '07 and loved it. We hardly saw a soul, hit about 11,000 feet altitude (I recall) and even drove through a few snow patches. The scenery and the driving is just awesome.
Fun, fun, fun in standard Discoveries, a Range Rover and a 110. More challenging on a bike, escepcially the rocky steps.
BTW it's not in the Sahara Overland book, perhaps it's in the Morocco one that I may eventually recieve when the postman decides to brave the snow!