Considering a 7 day cruise on the Paul gaugin cruise ship. Thinking we may stay an extra 3 days in either Bora Bora or Moorea..... Any preference or advice?

Both are very small islands - you can easily drive around the island in a couple of hours. Both have very high peaks in the centre surrounded by beaches and ocean. Very limited range of restaurants and shops on both.

Both are absolutely beautiful so I guess your choice could depend on the type of accommodation and facilities you want. Moorea is a short ferry ride to Tahiti so that could be a consideration.