Mark has done some serious math - he calculated it and it was something like 100ms and below is irrlelvant
consistency is all key. as a dueler, i can say a very large percentage of being able to play competitively is based on ping. it helps for reaction timing and for in game effects such as fast casting or even throwing well timed pots to things such as healing syncs. As it sits, i ping right at 45-60 consistently. This works for me because ive had to tailor my game a little bit to factor in the ping difference from the last location, which i was rocking 15-30. The difference isnt huge by any means, but i'd bet anything that its there.
Ive seen players who ping amazing simply outrun other players, mounts or not, just based on ping. This can factor in greatly when it comes to trying to split pot damage against your opponent. There are a few duelers on this shard with such low ping that i simply can not run their pots into them because they just out run me.
i really wish you would dig deeper into this issue and worry not just off of what ping says, but also the consistency of the ping. I would advise all the players to check these results multiple times throughout the day. Because believe me, nothing is worse than being fed a ping that can be anywhere from 15-105 and can change constantly within just a few seconds. At one of the previous locations, it was like this for me. I will not put up with the headaches this causes if your new move happens to be in a place with inconsistent and rapidly bouncing ping.
in short; i need consistent ping! Lower the better. But i would take a consistent 45-60 ping over an inconsistent ping with a window of < 5 - 105 any day.