The more expensive one is "modular" which means you can keep the cables you don't need disconnected from the PSU so they aren't cluttering up things inside the case.
Otherwise, the two are mostly the same.
This PSU is also a 750w Seasonic OEM PSU
http://www.newegg.com/Product/Product.aspx?Item=N82E16817207015
That is not modular, but it does cost significantly less after rebate. I have processed a rebate through XFX for my own XFX 650w and they gave me the rebate credit card quickly and without fuss.
All of them have 62A on the 12V and they all have the same OEM with (pretty much) means they will all power systems the same.