Never had a red ring yet, though had 1 HDD failure and 2 consoles with failed DVD drives. One was OOW so haven't had it fixed yet, but the first time I sent the first one in for repair, they sent it back still faulty.
The repair sheet you get back with it had a mark IN BETWEEN "DVD drive" and "Motherboard" on their checklist, like they weren't even bothered with what they did. Of course, plugged it in and the drive still wouldn't read anything. Straight back to them, and they did it right second time.
Still, from what I gather most of them are repaired by Teleplan, who are dodgy at best with regards to repair quality.