The reviews indicate that Onkei offers a variety of Japanese tonkatsu dishes with generous portions, refillable sides, and friendly service, making it a popular choice among diners. While many customers appreciate the quality, taste, and value for money, some express concerns over inconsistent food quality, small portion sizes relative to price, and occasional service shortcomings. Overall, it is considered a satisfying casual dining spot with a cozy atmosphere, though experiences vary depending on staff and timing.