The 430 is actually just revamped from their previous line, although it does live up to the 80% efficiency although sometimes it dips down to "only" 79%, the 500 and 600 are completely new from what I understand, and they also have the PCIe connector. You shouldn't have to pay more than $50 more for the 500W, I've found one for $120 (not as good as when Ewiz had them for $100 whereas the 430s are all pretty much going for $100 now (although you can find them for $85-90)...