I think it is a refurbished set. I asked if it is a new set... to which the Xbox Team replied, "Don't worry, we test all our replacement sets to make sure that they are working."
There is a huge design flaw. It needs a more efficient heatsink. Modders (who have voided their warranty) have documented that the damn thing will work after they did some mods to their heatsink.
Fortunately for me, I don't have a mod set. So, I can get it fixed.
But I think the Xbox team totally sucks. They are in a state of denial. So what if their games are good? Other game consoles have great games too.
They should have behaved responsibly and recalled all their sets to get them fixed instead of telling their customers that there is nothing wrong.
Trust me... Xbox 360 is a big mistake!