I would go with the Antec, just because I know I can trust their PSU's (used them before, have no reason to change basically) and they've been around for a long time. Not to mention it's cheaper.
Actually the Corsair is based off the Seasonic M-12.
Its modular, but the cable wraps are flat instead of rounded, except for the main 24 pin.
No biggie, both are awesome. I love my Seasonic, they power anything you can throw at them. Also, they're dead silent. 8)