On average, an overwater in Bora Bora during the high season will cost you around $1200-1300/night, whereas the same overwater bungalow in Moorea will cost you around $800-900/night.
For Moorea, the option to choose to fly or take the ferry makes it superior to Bora Bora, where your only option is to fly.
The honest truth between these islands is they both have incredible activities and it really depends on what you personally prefer.
In my humble opinion, the absolute best honeymoon would be well spent on both islands, beginning in Moorea and ending in Bora Bora.
Honestly, both of them are great and you really can’t go wrong and either island will be the best choice for you depending on your preferred travel style.