Me too, that's why i aways choose liquidation/aqua tail in the last generation and aqua tail instead of waterfall in older generations when a pokemon can learn at least both. However if the chance of flinch would be at least 40 or 50 without any things that stack, i'l would use it if the pokemon was faster.
(Most people use watterfall, because is "fashionable", have a "reputation" of being good, between quotes. They mimic what others say is good, bad, right, wrong and are doing.)
To really know what move works best for what you want to do, you'l have to forget the opinions and just understand how the move works, if you understand how it works, you'l automatic know what situation it apply best. You want to use a move that can get stack with a secundary effect? This effect will happen more than less with the stacks? You just want to inflict more damage using one move instead of hitting twice or more times? With the stab the move would be able to defeat more foes with one hit? In wich situation flinch would be indispensable?
Every move has his own strenghts and there are no better when it comes to this, you just have to choose the one who have the atributes for your particular strategy. Every strategy has a move that works best than the other. Only you know what you want to do exaclly. You want to use a move that makes the target flinch? Or you want to have a move that do more damage? A move that debuf the foes defense? What you gonna do if the secundary effects apply? You'le face particular enemies, or you'l face any? The secundary effect you are expecting is part of your strategy to create a particular combo?