An ace caff with quite a nice museum attached.

A wry, colloquial line of praise that reverses expectations: instead of saying a museum has a good café, it suggests the café is the main attraction and the museum is merely an “attachment.” The slang “ace” (excellent) and the casual misspelling/abbreviation “caff” evoke an informal, possibly British register, typical of offhand visitor commentary. The humor lies in the implied hierarchy of modern cultural outings—refreshments and comfort can rival or even eclipse the ostensible purpose (art, history, learning). Read this way, the quote lightly critiques consumer-oriented museum culture while still complimenting the overall experience.