If the amps are factory refurbished that means they were sent back to the company that made them and were fixed by them. So basically you are getting a used amp that is in perfect mechanical condition for a used price
I will throw my .02 worth in. I bought a Rockford Fosgate X6 refurbished and had to send it back 3 times to get fixed and finally on the 3rd time they sent me a whole other amp and it had problems and had to be sent back. It took me over 4 weeks of dealing with it before I finally just sold the other one as soon as I recieved it and that guy didnt have any problems. I just got 5 bad amps before I got a good one lol. I will never buy any Rockford amp again anyway.
My issue with refurbs, especially from ebay, is that they may or may not be factory refurbs, and good luck with warranty assistance from kenpoundsit864 in moosenuts Canada. It's a classic case of you get what you pay for. probably everything is cool most of the time, but why does EVERYONE have a story about how they got shafted on some refurbed deal? I just say buyer beware- I'll pay the extra scratch for a company to stand behind their stuff, but that peice of mind often costs me 25-50% more (wholesale to retail) but I guess I know what I'm getting. I prefer to shop around & get the best deal- which is why you are looking at refurbs in the first place. This hobby can be hella-expensive!