Wow, that's not a bad deal, Nice find!
20A on each of the +12v rails, is that good?
20A, not so good for a 1KW PSU. a decent quality 600W puts out more than that ampage wise.
I know i keep banging on about corsair but when i replaced i did crap loads of searching and they kept coming out on top so i'm gonna keep insisting they are better

, but as an example, the 650TX puts out 52A, the 750TX 60A and the 850TX puts out 70A. As you can probably guess, the model number=wattage, so the 650W one is chucking out 52A on its 12V rail, nearly 3x the amount of 1 rail and nearly half the output for the total supply and over 80% efficient and tested at those readings at 50 degrees, whereas that one is probably only at 20 degrees which is what the PSU testing standard is.
Also, bear in mind that the corsair ones have a single, dedicated rail because (they claim) it gives out cleaner power and makes it more compatible and efficient, but combined it is still more on it's one rail ampage wise than the 1000W one posted
for a basic scale, if you are running SLI or crossfire, 27A+ is your benchmark at the very least