As everyone else has written, this is a friendly, unassuming little place. It had a WC for guests to use.
We arrived at 12 noon on a Saturday, and ordered two sandwiches from the friendly lady behind the counter: a piadina with ham and rocket, and a cassoni with sausage and spinach. Both were delivered to our table after a short wait, and were tasty and warm, though the sausage meat was very greasy (oil dripped from it while we were holding it). Those two sandwiches plus a canned soft drink came to just under 10 euros.
It was an inexpensive and tasty pit-stop but I am not sure it warrants the top spot on TA for San Marino. I would recommend it but would also urge other travellers to manage their expectations!
There were numerous sandwich bars elsewhere in San Marino, so this wasn't a one-off.
Finally, we weren't given (or offered) a free Nutella sandwich, in case any other travellers thought that one would be coming their way as per some of the other reviews below! However, if you'd like one, you could order one - we saw from the extensive menu that the sweet sandwiches were not expensive.