I would probably upgrade to a Rock Shox Tora series. As for used/new, this is a part that takes a pretty good workout and usually its not much of an issue. BUT the biggest thing with suspension forks is being able to take a close visual inspection of the Crown, fork brace and Stantion Tube to see if there was any hard hits taken.
I tend to shy away from something that is in direct contact with the rider and the ground. Derailleurs, shifters, brakes is another story.
So IMHO I would buy new for a suspension fork.