It's built by an OEM called Andyson. A lot of their units seem to have unrealistic 80Plus ratings. So I don't think it will be as efficient as it claims to be.
Voltage regulation +12V rail(s) on the 1000W version are a bit loose, but still in spec.
Personally I would not want to buy it. Especially if you are overclocking and adding a second GTX 580.
My other option for this build would be Antec High Current Gamer Series 750w
which is made by Delta, would this be a more viable option?
My build is actually overbudget by a bit already, so I'd like to not go over $100 on the power supply if at all possible. If I need to go down to something smaller for the time being to be in that range, but not be SLI ready, I'd be ok with that as well. I just want something that is going to last quite a while, and the Antec comes with a 5 year warranty, so I figured it must be pretty good.