The Coral Sea and Ribbon Reefs are definitely that much better. Re: tipping, I am Australian and if I go to a restaurant and I think they have gone the extra mile...I tip. If the taxi driver is helpful, helps with my shopping bags...I tip. I have worked on liveaboards from backpacker orientated through to upmarket and it is HARD WORK, draining (mentally and physically), long hours, and a lot of time away from home. I always used to try and go the extra mile and when people showed their appreciation through a note, a gift, a special comment, that is when I knew it was appreciated and it encouraged me to keep doing it even if I was dog-tired. I have now given up the water (much as it saddens me) due to the time away from home, missed birthdays, missed Christmas's etc. Yes we do it for the diving, because we love it and what better job satisfaction then making someone's once in a lifetime holiday that much better...but if the crew do a good job, please let them know it however you feel appropriate!