Snipers are one of the few classes that can mitigate PT's ridiculous elemental damage. They have enough CC to keep them outside their 10m comfort zone while being immune to both pulls and leaps. Add in the fact they have massive amounts of damage and if conditions are favorable you can 100-0 a PT.
Like I said though it could easily go either way with a sniper. Most times PTs will win flat out because the sniper is bad though. Snipers, like marauders, are punished pretty harshly for poor play whereas PTs are pretty faceroll.