Yep, love the Geeks.
Used is used but everything I've ever bought from them has been in excellent shape and lasted plenty long enough (nothing has died thus far).
Buying one of their used chips, depending on how old it is, doesn't necessarily mean it only has a 30-day warranty on it. They usually get boatloads of these chips and some could possibly be used retail chips that have original warranties on them. In the case of Intel chips, you would only need to call them and give them the numbers off of the chip and they'll let you know if it's still under warranty or not.
Never had to RMA an AMD chip so I'm not sure about their policies but I'm sure it's probably close to the same.