Even with cheap power you will never have a positive ROI with them. Your only chance would be if the value of BTC increased significantly or the difficulty plummets.
Call me crazy, but i feel lucky i might get something delivered at last.
According to BA the X-1.5 runs 160 GH/S on 100W. If that's true i'll be looking at them for at least a couple of months (i don't have very expensive electricity).