i reviewed both of them and they have the exact same spec............ how can the quality be worse if they have the same things?
All 5770s should have the specs, but the cooler/PCB design could be radically different.
The "ATI branded" card could look like this: http://www.newegg.com/Product/Product.aspx?Item=N82E16814141116&cm_re=HD_5770-_-14-141-116-_-Product,
which exhausts air inside your case and has a fan that doesn't cool as well. It also could have used cheaper parts like capacitors, and be badly made.
Since its more expensive anyways, just get the Sapphire, which looks like a reference design. Sapphire makes good cards.