Since you will probably using a taxi to get to the hotel and then to the airport - it probably doesn't make too much of a difference. The drivers know how to maximize the streets and times. And if you have an early flight out (I know when I fly into the States I am usually flying out of Florence before the cock crows ....) - then traffic is minimal.
However I can offer that at the moment there is quite a bit of confusion/construction near the SMN train station (more than normal :-) ) so if you find a time schedule that works for you then Rifreddi could be a excellent alternative.
Buon Viaggio - and enjoy Cinque Terre,