Difference with these Corsair PSU

[xh4n]

Is there any difference with going wid a 550W / 520W / 620W?

The 550W seems to be the cheapest. cheaper then the 520W. is there any difference?

 

[XMSYellowbeard]

The HX series are modularm the VX is not. Other than they, they will all perform similarly.