As far as the conservation orientation UE is a unique operation. They have research projects going on and make daily educational presentations to the passengers. They have even produced a film on the Minke's that they sold to National Geographic. The whale experience is done with snorkels and everyone holds ont a line behind the boat. From the film it appears to work as the whales get comfortable with the setup and approach the snorkelers.
On our trip they captured and released live Nautilus critters. Also they have installed tracking and identification devices on many of the resident sharks at Osprey. They hauled up a few to measure their growth and then released them.
It is a really fine boat, I was just on it at the end of October. The Chef was great and the crew very helpful.
It is true that they schedule 4 dives per day maximum rather than 5, but only a few dives had a bottom time limit and that was usually an hour. Otherwise, the rule was come back to the boat with your buddy and 500 psi. You could also do more than 1 deep dive per day. I don't remember anyone complaining about bottom time. It was more like people were reaching the limits of their endurance by the end of the trip, and most of them were in their 30's. (On Minke trips the do fewer dives than at other times.)
If you think Port Douglas is far from Sydney, it is a whole bunch further from Houston TX where I live. Besides, there are other things to do up north and Port Douglas is a neat town.