Alleva

I recently learned of this SE approved meatball sub from this Italian dairy around the corner from our office.  It was such a welcomed surprise for someone who has become completely jaded about our downtown Little Italy.
And good it was.  Just like Serious Eats says, the meatball itself is the real highlight.  Soft, fluffy and flavorful.  And while the generous tomato sauce soggies up the bread, the sandwich never gets too messy and the tang only enhances the meatballs.
Alleva, 188 Grand Street, New York, NY 10013 (at Mulberry)