Wattage isn't everything in a powersupply. In my past experiences, brand does matter. When you buy a brand, you tend to buy quality. Enermax, Antec, and Sparkle are among my favorites. A 400W no-name could easily be outpowered by an Enermax 350W. It's the design and special attention and care that is put into the engineering and manufacturing process that makes a powersupply so good.
Just FYI. 🙂
Good lucK!