We recently went to heron for about 4 days. The island itself is beautiful, awesome beaches for chilling out, really quite good food and nice rooms. We were lucky enough to be there right at the end of the turtle hatchling season and saw a few of the little guys emerging one night. That was a real highlight.
The diving... I only did three or four dives there, including their 'signature dive site' Heron Bommie. I was quite surprised at the amount of dead coral and coral covered in silt. There really wasn't the amazing colours and formations I was expecting. Heron bommie was a pretty good dive with a manta cruising past for a few minutes. Plenty of turtles around, reef sharks on every dive. Not a huge amount of big fish life, and the DMs moved to quick to sit and search out the little stuff.
I found the dives to be heavily geared toward inexperienced vacation kind of divers. Max bottom times are indeed 45mins. They also tell you to let the DM know when you are at 100 bar, and at 70 bar, at which point you are to begin your ascent... Even if you are at 5 meters, directly below the dive boat...
On my first dive my buddy signalled he was at 80bar, I signalled I was at 90bar and the DM signalled for us to ascend! We both signalled WTF and she told us again to ascend...Total dive time was 33mins!!! Back on the boat she suggested I take a larger tank next time to extend my bottom times! I told her I surfaced with about 85bar and she said oh well, you buddy signalled 80bar, which is close to 70bar...and you didn't miss much on the end of the dive anyways.
They have no interest in the buddy system, it is herd diving unless you hook up with someone on the boat.
On the plus side, the boat is easy to use, plenty of space to gear up. no more than about 10mins in the boat to get to any dive site. Their hire gear looked to be in good condition. (I didn't use it, that's just what it looked like to me). They rent Al 80s and 15L steels. There is plenty of snorkelling around the island, but we found the wreck on the edge of the channel to be the best spot.
It's a great place to go and relax for a holiday, nice pool and bar area, and a really beautiful island. If you're after mind blowing coral reef diving, I personally would look at the other options.
If there's anything else you want to know I'll try and help if I can.
