I travelled to the outer Great Barrier Reef with Sunlovers yesterday, along with my parents, while over from Perth. I'm glad I didn't read the reviews here before leaving as most of them don't represent what an absolutely amazing trip this is!
We had perfect conditions and the reef was fantastic with a huge variety of coral. The number and colours of the fish blew me away. I lost count but think I easily saw 50 different species of fish, with 5 different types of colourful parrotfish alone! With your ears underwater you could hear (as well as see) them pecking away at the coral, truly like something from a David Attenborough documentary. The fish are literally all around you. There are giant clams and also the enormous sex-changing humphead wrasse Walla to take pictures with. To top it off we even got lucky at the end of the snorkel and saw a reef shark!
A special mention to Pablo who does the educational side of trip. His enthusiasm for the reef is brilliant and you can tell he loves sharing it with everyone. We did the private 40min snorkel tour with him and would highly recommend it. You get to go outside the designated passenger snorkel zone. My mum isn't a strong swimmer but you can choose to go with a safety ring that Pablo tows behind him so you don't even have to worry.
The boat and toilets were clean. There were even freshwater showers and changerooms on the pontoon which was a pleasant surprise. The buffet was perfectly adequate. But really you don't go on a trip to the Great Barrier Reef for anything other than the reef itself, which was superb.
Just a note that this isn't a small tour group so if that is what you want then book elsewhere. Having said that, I never felt crowded in the water and I would estimate that about 1/3 of the 230 predominantly Asian passengers didn't even snorkel. People are in and out of the water doing different activities, so at a rough guess I don't think there were more than about 50 people in the water at any one time.
My only regret is that I didn't hire an underwater camera which you can do for $55. I still go away with memories for life though!