I have done both at different times: Taken a ship's tour that included - The Curaco Liquor Factory (this is a joke compared to Anheiser Bush!), a native plantation house, the Sea Aquarium (which I truly enjoyed) and of course a drive through the country side. The Taxi tour we were left at the Sea Aquarium Beach and picked up at a specific time then returned to Downtown for an "on our own" walking tour including the Floating Farmer's Market, Synagoge, old fort and the Hotel (besure to stop there for a cool drink out by the pool at the breakwater of the canal. We walked back across the Pontoon Bridge and to the pier which was a great way to spend the day. Curacou is very flat and desert like - but the people are friendly and I felt very safe accept near the Floating Market.
Bon Voyage