The Canyon is not dangerous. "Darwin award candidates" are those who destroy its reputation.
The Canyon goes all the way down to 60meters (and perhaps more). I have seen someone who made his first dive after AOW there, and went out of the Canyon at 50meters...
The Canyon's top close to a very small fissure. Most of the time there's no exit from it! It is more like a long cave than a Canyon. The entrance is through a small tunnel at ~18meters. Then you come inside and there's no way out until ~30-35 meters. Next station out is at 46meters, and after that I don't know.
The bottom is sandy, so a careless diver will destroy visibility for all the rest. Better be the first on e in the morning to get there.
Inside there are not so many fish, especially if you are there after a dozen of other groups. However, it is an exciting site.
Theo is right about sites like Abu Helal. They are great places, not so popular. However, tide and waves can make these sites problematic. We once were crashed there by the waves on the top of the reef and got plenty of scratches and damaged our suits.
The bell is one of my favorites. The wall there is beautiful!