I think A & H is advertising that the xone:dx is compatible with DJ software other than ITCH. Check out the specs at
http://www.xone.co.uk/
If thing is compatible with TPro AND as responsive as the VCI-300 with ITCH, I would jump on this and go back to TPro in a heartbeat.
(ITCH is gonna try and make a run at Traktor with 4 decks and built in effects in a future release. You tube videos for this piece of kit and you'll see working 4 deck versions with effects of ITCH.)
It comes out at the end of this month!!!