I have (and recommend) a normal cam strap at the top of my back plate and one like the scuba pro that you linked to through the lower slots near the bottom. It makes changing tanks much more convenient than trying to get a normal cam strap on the bottom to slide up over the tank after a dive, especially with weights in the pockets I have on my waist belt.
It can be a pain to get the ring end on the hook end sometimes but I think that is because my quick release strap is fairly new and is still stretching when wet. I also found that the model I have (from Edge-Hog) that on a 12L tank (approximately the same dimension as as an AL80) that the hook side of the velcro completely overshoots when the loop side of the velcro. I am using a couple of sections of mt bike inner-tube to manage the tail of the strap and so far it has not slipped. I may, in time, get a local shop to sew some more velcro in place for convenience though.
-Z