The Antec was built by Delta. It's a good unit, although there is a similar Delta-built one that recently was not awarded at HardwareSecrets, apparently due to some quality issues.
The XFX is built by Seasonic. Seasonic does not know how to build a bad PSU. Also because it is modular, this is the one I'd choose out of those two.
Flip a coin or go with the cheaper unit. Either one is a great chioce for a high end gaming build. The only units I would consider over either are the Seasonic X series or the new Seasonic Platnium series.