I had purchased an Antec Neo 550 PSU that ran great since last November, then inexplicably died. After removing the PSU from my tower, I noticed that it was making a strange rattling sound like a piece had broken off inside.
Antec's online RMA process was easy to complete and I received an RMA number 10 hours later. After boxing and shipping off my dead PSU, I received a brand new one as a replacement.
The service was quick and efficient. Awesome company!