Bottom line
Maison d'Or (39 residences, pre-construction sales, late-2028 targeted delivery, from $5.7M published guidance) and South Flagler House (about 105 residences, under construction, from $7.98M advertised) are the two South Flagler waterfront flagships. Maison d'Or suits buyers who want a smaller, newer project and can wait for delivery; South Flagler House suits buyers who want an under-construction building with a larger residence program.
Both sit on the South Flagler waterfront, so the choice is not corridor but project: boutique scale and a longer timeline versus a larger under-construction program. Compare residence count, delivery timing, published pricing guidance, view exposure, privacy, and service structure — then verify current availability, fees, and contract terms directly before deciding.