From my personal experience, I can say that the mozzarella in this shop is good. Definitely good. The staff is kind and helpful. I read the reviews, but honestly, I've been going to this shop for over 10 years and have always found them kind, courteous, and helpful.
The sign says that the mozzarella comes from Salerno and the quality confirms it. Their 500 gr round buffalo mozzarella is really good. Also available in the 1kg version, also as a braid. Must try!