Very interesting post,
@Bruno Genovese ! I realize it's old... Just reading it now.
There are review sites like Trip Advisor. They work better for dive destinations than for local dive shops offering scuba lessons in a local pool before going on a dive trip - but they work. A few answers above included a few other places where you can find reviews of dive operators. OK. But...
Isn't it weird that these dive industry brands (PADI, SSI, Aqua Lung, etc) have so little interest in making sure their brand is 'not' associated with a dangerous operator? Or even an operator offering a bad customer experience? A brand, by definition, is build on the consistency of the quality of the experience - at whatever level you want to operate. Nobody goes to McDonald's for a $500 dinner - and vice versa. But you know what you're gonna get.
Even if none of these dive centers are franchises (they are independent companies), I'm convinced it would help the dive industry if new customers just starting to dive could go to a dive facility under "Brand X" and "trust" the quality of service they would get. No?