[pkroll]

"Mediocre" is virtually always considered "poor" in the USA, even though the literal definition is "middling or average." Anyone would consider going to an average restaurant, but we'd avoid one someone described as mediocre.

[mjevans]

If I want a lot of OK sushi I go to a place I trust for that. It's mediocre, but priced accordingly; and thus has good value for the money.