Cook's Illustrated reviewed Pecorino Romano, which they say is in the shadow of its more famous cousin Parmigiano-Reggiano. I've read elsewhere that Romano is usually a better choice when recipes call for Parmesan. The Cook's Illustrated article also says that "Pecorino Romano" generally refers to imported cheese from Italy and is made with sheep's milk. "Romano" refers to domestic cheese made with cow's milk (sheeps milk being very difficult to obtain in any bulk in the US). In general they preferred the imported stuff. They also said they reviewed cheeses "widely available in U.S. markets". Yeah... right... heard it before...
So anyway their winners etc are:
Recommended:
Boar's Head Pecorino Romano
Locatelli Pecorino Romano
Pecorino Romano by Zerto
Genuine Fulvi Pecorino Romano
Recommended With Reservations:
Sartori Cheese Romano
Stella Romano Cheese
Bel Gioso Romano (this one I can actually find)
Several years ago they reviewed Parmesans, their choices were:
Recommended:
Boar's Head Parmigiano-Regianno (imported from Italy)
Il Villagio Parmigiano-Regianno (imported from Italy)
Belgioso Parmesan
Sarvecchio Parmesan
Recommended With Reservations:
Rosalia's Trattoria Parmesan
Not Recommended:
Kraft Grate It Fresh
Stella Parmesan (for Romanos, Stella is listed under "Recommended with Reservations")
Digiorno Parmesan