Depends. Do you have a power cable already? Because notice the Antec's last detail:
"“Green” with No Power Cord Included The Antec EarthWatts EA-650 Green meets 2010 EuP requirement (5Vsb < 1W) for ultra-low standby power consumption. By reusing your existing cord, you can reduce waste and help protect the environment. "
I'd get the XFX. Its $20 cheaper after rebate. XFX is just a Seasonic PSU with a different badge on it. Corsair used to do the same, but CWT now makes their PSUs. I know the Antec's used to be Seasonic, but I think Delta now makes all of theirs. While Seasonic is obviously the best of the three, all 3 companies make fine PSUs.