The history of these tomatoes is rich in history:
The story goes that the first seed of the San Marzano tomato came to Campania in 1770, as a gift from the Kingdom of Peru to the Kingdom of Naples, and that it was planted in the area that corresponds to the present commune of San Marzano. They come from a small town of the same name near Naples, Italy, and were first grown in volcanic soil in the shadow of Mount Vesuvius. Compared to the Roma Tomatoes with which most people are familiar, Marzano tomatoes are thinner and pointier in shape. The flesh is much thicker with fewer seeds, and the taste is much stronger, more sweet and less acidic. Many people describe the taste as bittersweet, like high-quality chocolate. Because of their high quality and origins near Naples, San Marzano tomatoes have been designated as the only tomatoes that can be used for Vera Pizza Napoletana (True Neapolitan Pizza).
At the Oak Brook Costco, we ran into this HUGE can of NINA San Marzanos (That's them in the photo above). $2.89 for the really big can. And....the "pros" say that they are legit, according to this post on pizzamaking.com. The one complaint they have is the water-content; which doesn't bother me. I recently made pizza on our grill and hand-drained the tomatoes from the can - squishing them to remove some seeds/moisture. The real revelation for me came from the infrared burner on the back of the grill. Up to this point, it was useless - in fact I've never turned it on. But...with pizza on the grill, the burner creates a lot of top-heat, browning up the cheese/toppings.
The Nina tomatoes were a great compliment to our home-grown basil for our margharita pies.