Steve Miles
Google
The trip was excellent, we went with Divers Den, comfortable fast boat, choose to dive or Snorkel, regular snacks, lunch and very friendly and helpful crew. For safety reasons you only get beer on the way back.
Booking can be a bit confusing because Google tours and you get mostly agencies responding and not so easy to identify which cruise you are on, we booked direct via hotel reception.
We were 2 x 55+ year old brits, I am a competent swimmer, in a pool, but rarely swim in the sea, rarely snorkel. I found it difficult to avoid swallowing half of the sea.
The wife had more sense, less machismo, she happily wore a flotation vest and got towed around the reef by a tour guide, got to see a 3.0m White Tip Shark barely a few feet below.
My advice is go for it, certainly try the dive, first one is free, only caveat is if you don't have experience either practice first off a beach or drop your pride and get towed with flotation aids. The guides really don't mind, they want you to get the best out of your experience.
Staying onboard has it's advantages, I got lots of chats with the Captain who has a really dry sense of humour, he put 2 experienced divers far out over the reef, explained it as the nautical equivalent of a naughty corner.
I also met ex pat Kenyan guy who started the tour diving off Barrier Reef and was a real enthusiast, can't guarantee you get him on every trip.
Book and enjoy.