Both are SLI and Cross Fire ready but given the better numbers and features of the Antec psu I would say that the choice would be Antec , however you would be ok selecting either one as they are both quality power supplies.
The nice thing the XFX PSU's have going for them is in many test's that I've seen the voltage stays rock solid and moves less than comparable PSU's would. From owning one myself I can also tell you that they are very quite, and stay very cool (although mine doesn't have much of a load on it). I would still say the antec, more power, and the efficiency bump doesn't hurt. Depends what the price difference is though.