Is fleet footwork rune or phase rush rune better on fiora?

If you had to choose between the two, go for fleet. The movespeed together with your passive gives more than enough to proc your ult easily and the sustain is really valuable. The only time I'd go for phase rush is against something ridiculous like Nasus with his 5 second slow. That said, on Fiora you should really be bringing Press the Attack in offensive matchups, Grasp (bruiser Fiora can stack tons of health), or the current meta high-elo stone, Klepto.