I know its hard for all of us to plop down $200 for new tires that haven't been reviewed much yet. So I took the plunge and bought the new 320tpi Vittoria XM tires.
If you don't really want to read the lengthy review, here it is in a nut shell. Its a really nice tire and Vittoria stepped up their cross tubular game with a new super supple casing and new sticky rubber (two major complaints of the older tires). The tread design is great, gives you grip and sheds mud. But as most tires, this tire is pretty condition specific. I found it works great in heavy mud but rolls slow when the course dries up.
Hey Jon Page rides these and he's sponsored by Challenge so its gotta be good (second picture on his front page)