Pershing wipes the floor with the Germans in simulator battles, I currently hold a 90% win ratio in 30 battles or so with the M26. It might not win frontal battles with Tiger IIs (though with 250 penetration apcr it stands a fair chance), but it mostly faces Tiger I, Panthers and Jagdpanthers which aren't much of a problem frontally. From the sides, the 90mm makes sure everything blows up with one shot to the ammo racks.
As long as you use the flanks instead of trying to pick frontal fights, you'll be completely fine. Most of the time the US team of 6 BR (is that what the Pershing has? Idk) roflstomps the Germans. The only times the Germans win is when they can camp the road to the victory point with Ferdinands and Tiger IIs.
In simulator battle the Pershing is considered a medium tank (despite the fact it has the gun of a heavy) and is thus favored over the Tiger II, having an extra spawn.
I've oneshot so many German heavies/TDs I was literally beginning to feel sorry for them for sending them straight back to the garage all the time.
Edit: looked it up.
33 played, 29 won. Respawns 41 (don't die that often so I rarely need the second spawn).
109 ground targets destroyed.