My go to joint in the city for seafood platters. Extensive selection of oysters, clams etc. Reasonable price, quick service and competently shucked oysters.
Try the sea urchin at your own peril though, haven’t had much luck with the Maine variety.
Added bonus, you get to personally scope out the selection and I love the handy oyster guide above the counter indicating size and salinity by oyster varietal.
Pic from schiller-wine.blogspot.com
As for Grand Central Oyster Bar, go once just to check the box and soak in the admittedly nostalgic atmosphere and the hard to find Maine European flat oysters (pictured below). But generally forgettable to downright horrid experience foodwise. During my last visit a couple weeks ago (not pictured), the oysters were so poorly shucked and experienced an utterly abysmal service at the oyster counter (located at the shucking area).
Great product marred by the incompetent staff. Last time I ever visit that place.