Yes I've had Nick's, and yes I've had Mamas on the Half Shell's oysters. Not thrilled w/ either.
I happened to be at Fells Point this afternoon, and stopped by the Fish store at the Broadway Market on Broadway and Eastern Ave.
The Fish Store (sorry I didn't get the name) just had few bar stools in front of a mountain of shellfish. Ordered half a dozen raw oysters.
WOW!!! They were huge, plump and absolutely fresh. Each morsel of oyster was bathing in nectar, and tasted of fresh sea water. These are singularly the freshest oysters I've had since Blue Ribbon in Brooklyn, NY.
And a 1/2 dozen cost me only $4.50 + $1 tip.
I'm definitely going back when I get a chance.