Hey knotknut... Thanks? As I said earlier, I expect an OP to provide necessary info for a product they have concern about, not have to do legwork myself. I don't find asking someone to help themselves receive help an unreasonable request...
The PSU's specs look OK, but I can't find any reviews of any Ace PSUs, so it's impossible to gauge it's comparative quality. The 12V rails are a bit on the weak side, though... I'd have to guess this is a 550W peak/maximum output PSU, not a 550W continuous one. It's probably rated something along the lines of 400W continuous.
Does the place you intend to purchase it from have any further details? Perhaps a photo of the power ratings or customer reviews?
Without more info, I'd just seek out a more reputable brand. Antec, Corsair, SeaSonic, Silverstone, CoolerMaster, etc.