I have had nothing but great experiences booking tours from tour companies not affiliated with the cruise line....have done so in Fiji, Mexico, and Tahiti and have saved a lot of money. The on-shore tour operator's business depends on them being on time, providing good service, and referrals. Before cruising, I spend a lot of time on trip advisor reviewing the destination and tours. When I decide on an excursion, I then book it on-line before I leave on the cruise. That way when I arrive in port I'm good to go. However, you need to remember that if something goes wrong, and you miss the ship, you are responsible for meeting up with the ship at the next port destination.