Of the three "engagements" Americans had with Tiger I's, the Pershing lost the engagement it had with one of the tigers. It was knocked out and later repaired, but it lost.
I don't know about vs Tigers but I know of a story of supposedly the only T26E4 Super Pershing engagement with a KT in Dessau and the Pershing won after switching to AP rounds and piercing the ammo hold (I read the article in my Military Heritage magazine referencing an interview with an eyewitness gunner). I later read that according to German military records, there were no KT's within miles of that area during the time it happened so it likely was either a Tiger 1 or Panther or a classic exaggerated re-telling of an engagement.
As others have said, you can't look at things just in 1v1 vacuum. How a tank/vehicle should be measured is it's mobility/firepower/survivability/fit within rest of armor corp/etc. If you just look at Puma for instance on paper, it is decent but nothing special. However in mid game 1 v 1 when there isn't a swarm of armor and AT everywhere like in late game or 3v3/4v4, the Puma (Ostheer, mobile defense) is my favorite unit of all. It hits hard, it has good range and is fast with smoke so it can solo SU-76s, T34's, M4 shermans and if it starts to get into trouble it has mobility and smoke so it is very good at surviving.
TL;DR don't put too much stock into head to head match-ups, face to face with no support on either side as that rarely ever happens in real life or in COH 2. Even when 2 tanks do meet up, before the duel is over one or both sides has usually been able to bring up some kind of AT to try to tip the scales in their favor.