Go with the Antec before it is sold out too. What are your system specs cause 750W might be a overkill for your PC.
My system built is:
CPU: Intel Core i7-4770K 3.5GHz Quad-Core Processor (Purchased For $389.00)
CPU Cooler: Corsair H100i 77.0 CFM Liquid CPU Cooler (Purchased For $139.00)
Motherboard: Gigabyte GA-Z87X-UD3H ATX LGA1150 Motherboard (Purchased For $229.00)
Memory: G.Skill Sniper Gaming Series 16GB (2 x 8GB) DDR3-1600 Memory (Purchased For $159.00)
Storage: Seagate Barracuda 2TB 3.5" 7200RPM Internal Hard Drive (Purchased For $96.00)
Video Card: Gigabyte GeForce GTX 770 4GB Video Card (Purchased For $569.00)
Case: Corsair 400R ATX Mid Tower Case (Purchased For $105.00)
Power Supply: Corsair Professional 750W 80 PLUS Gold Certified ATX12V / EPS12V Power Supply (Purchased For $185.00)
Optical Drive: LG GH24NS95 DVD/CD Writer (Purchased For $19.00)
Operating System: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit) (Purchased For $108.00)
It has an estimated wattage of ~450, and i will potnentially be overclocking and adding a second GPU in the future (when the 770 starts to become a little slow/old), and i would rather have to many watts than not enough.
too late, already bought everything. I won't be getting another card for a while, not until the 770 starts to become outdated, in which case i will probably build an entirely new computer. Also, because no-one picked it up, i'll put it here and on my other posts, G.Skill Sniper Memory is for AMD processors (at least according to where i bought everything from)