I had a 665 before it fried itself and they replaced it with a 670.
The last 2 years should be safe as they are backed by insurance according to the administrators statement posted on their site:
My 665 also fried itself but they just replaced the GPU on mine, as far as I know.

Sounds vaguely promising on the warranty, I guess one would have to contact MS (Mobile Support) if there are problems?
Or just buy a Dell.

