Ambiance: Nice coffee shop vibe from a sandwich shop, I like the bright colors they use and the entryway lets in a lot of light. It's a little cramped when you walk in but thankfully they have seating which extends into the back of the building as well as a few tables outside. Water is self-serve from a countertop cooler. Service is friendly and they'll readily help you if you you're having difficulty deciding what to get.
Food: I've tried all their sandwiches and can say they're all fairly tasty. I feel there is some bias to the American palate as you won't find strong flavors of pâté or pickles (do chua) and the heat from the jalapeños+sriracha is relatively tame. While not the most authentic tasting, the ingredients do taste very fresh and the meats well-seasoned. The rice flour baguettes are also the real deal, airy and crispy.
Overall I like Banh Mi & Ti as they offer nice clean flavors and use quality ingredients in their sandwiches. I'd recommend this place or Ineffable Ca Phe if you have a hankering although don't expect "down and dirty" bold flavors like the shops in Los Angeles.