I would never buy refurbished components, but wouldn't refrain from buying a refurbished notebook, monitor, or peripheral.
Refurbished components are invariably the ones of a lower quality which were returned.
With notebooks, the "odds" of getting a *trouble-free* machine buying new is considerably higher than refurbished, especially considering most refurbished were problematic (even some lemons) ones returned to Apple. The odds are considerably higher of getting a trouble free experience when buying new.
However, if you get lucky, can't beat the bang for the buck for the refurbed notebook that was returned as an open box, or unaccepted delivery, or a never paid pre-configured one.
There's only one risk buying new. While the odds of receiving a DOA new is astronomically slim, every new notebook (any new computer component with chips) may "die" during the burning in period. With a new one, when the chips have burned in completely after about 3 to 5 days without issues, it'll basically run forever.