A new CPU would be better only because of the warranty, but Intel CPUs very rarely fail as in hardly ever. A used CPU could have been abused, and may not overclock as high as another CPU, but that goes with any CPU new or used. Some overclock more than others. A new i5-4690K would cost more than the original new price simply because they don't make them anymore. Kind of like finding a completely stock, excellent condition antique car (though the i5-4690K isn't exactly antique, they just don't make them anymore) the car would cost more now than it did when it was new. Supply and demand. So it's better to pay $115 used than $300 new.