While we were in St Lucia recently, we used Airport Shuttles for 3 trips between hotels, port and airport.
Each trip was relaxing and smooth and the drivers were pleasant and helpful. The vehicles were air conditioned and therefore lovely and cool and we had bottled water supplied as well.
We were held up for sometime before one trip and the driver was not phased by this at all.
We will always use this company when we travel to St Lucia.