If you have a choice between trains that go to grand central vs penn station always pick grand central. The arrival experience difference is night and day, especially if you care about aesthetics and atmosphere

Grand central is gorgeous with the main hall and decent food court. Penn station is underground chaos with terrible signage and construction everywhere. Like literally everywhere

Metro north uses grand central. Amtrak uses penn station unfortunately, and LIRR now uses both penn station and grand central via the East Side Access project. But seriously grand central is what train stations should look like - penn station feels like architectural punishment