While Corsair sells some veru good PSUs, the CX and VS series are not among them. Relying on brand name, model name and even tier lists is unreliable as all units within a model line are oft lumped together and often, underservedly so.
Both those PSUs are "budget" models not well suited for the strains of gaming or overclocking. If an office box, used for simple word processing and web browsing, the CX430 will serve you just fine, but the capacitores are such that I wouldn't subject them to the aforementioned gaming / overclocking loadings. The Seasonic S12 / M12 series is affordable and sometimes the 620 watter is cheaper than the 520 watt model.
The EVGA B2 750 was $44 last week bit is now up to $60 @ ncixusa.com
The B1 series is a bit cheaper but is not up tot he quality of the B2 series and I would be hesitant to use with overclocking or gaming. OTPH, some
have a 10 year warranty, so if ya don't mind the potential RMA, you are guaranteed to be supplied with a working OPSU for 10 years. Other options
Antec HCG 520 ($55)
http://www.newegg.com/Product/Product.aspx?Item=N82E16817371058
Seasonic S12 ($58)
http://www.superbiiz.com/detail.php?name=PSS12II520&c=CJ