Shunshin, the speed and distance you travel is determine by the chakra control you use in your feet. More chakra will give you more speed but you have to be able to properly control it or you'll end up like KM Naruto when he couldn't control his speed and broke his ankle while attacking Kisame.
Currently Naruto probably have the highest chakra reserve in base in addition to Hashirama's cell boosting up his stamina even more. We saw Naruto's chakra control greatly improve in The Last when he was using FRS with 1 hand when he use to need 2 clones to help him in War arc 2 years previously. 10 years later and it should be even better so his Shunshin skills, if trained as I believe it has been, would be the fastest around as he has the chakra and chakra control over everyone else we know of.