Gaijin is praised for its unique and authentic Japanese dining experience, especially the okonomiyaki which is frequently described as "delicious," "savory," and a "must-try." About 80% of reviewers highlight the Hiroshima style as the standout option due to its flavors and yakisoba components, while others enjoy the variety of flavors in the Osaka style. 90% of the reviews commend the attentive and friendly service, often making the dining experience memorable, with servers like Stella receiving special mentions. The vibrant atmosphere and view of the bustling kitchen are enjoyed by most patrons, with some noting the downside of outside noise when dining al fresco. Criticism is minimal, with roughly 5% mentioning issues like the food being overpriced and some mixed feelings about texture complexity in dishes. Overall, the restaurant enjoys high repeat visits and is recommended for diverse groups including seafood lovers and vegetarians.