Is this PSU any good (ebay link ) Powercool 750W ATX Modular 80 plus

I would say no since its not a well known brand so you can't be sure of the components inside. My PSU has 52 amps, which I think is among the highest.
 
I have never heard of the brand and can't seem to find any legit reviews therefore I would stay away. 64 amps is pretty impressive for a 750w PSU though, my Corsair 750TX only has 60 amps. For those of you that think that is alot the Corsair AX1200 has a single 100 amp rail !

Look for a power supply from Corsair, Seasonic, PC Power and Cooling, XFX, Enermax, Silverstone or Antec. This list is pretty up to date.



http://www.eggxpert.com/forums/thread/323050.aspx
 
It has two 32A 12V rails. It cannot be assumed that they can both be loaded to 32A at the same time, especially not on a unit of unknown, likely low, quality.
I heard off someone who owns/owned one and he said that the 750W number is the peak figure rather than the continuous figure, which is another indication that it is a low quality unit.

What do you want to upgrade to? Maybe you don't need a so called '750W' unit and would be better off with a high quality ~550W unit.
 



Yep, that is a solid power supply.