I had a terrible fuckin' experience with MS and my 360.
Middle of Jan. my Box died after doing a console update and a Gears update. I got the three flashing red lights. I called, went through all the troubleshoot problems and they sent me a shipping box. I got it back about three weeks later, started playin and I was having "gaming artifacts" all over the screen after about 10-115 minutes of playing. It was like lines, shapes, spots, all kinds of crazy shit. I called customer service, they said I had to send it in again, I talked to a manager and he said I had to send it in again. I told him I didn't want to do that, he said it was my only option and offered me a gift game (I chose PGR3 over Kameo). I asked what would my options be if I got it back and it still wasn't functional, he said I'd have to send it in again for repair. I didn't like that much, but it was my only option so I sent it in for the second time. Three weeks later, I got it back, SAME EXACT FUCKING problem. I called, demanded to speak to a manager, told them that I've sent my console in twice and that I wanted it replaced. They forwarded my request to the "Repairs and Replacement" department, and they approved me to get a replacement console. So I sent it in a third time, three weeks later I got a new console which was shipped in a retail box inside the shipping box. Included in the retail box was a brand new wireless controller as well, not sure if that was an accident or not. So yeah, I was without my $400 console, numerous accessories and 11 games for a little more than two months and it was fuckin' frustrating as hell.