Checklists are what you will use in the airlines. But if you work for a company that uses something else eg flows or memonics then use that. Always use what ever the Chief Pilot wants you to. Thats who you work for and thats who will fire you if you don't. If something is inadequate in the system that your company or flying school is using notify the appropriate people and explain why it is wrong objectively. Because you do it differently isn't a good reason to change something and standardisation of operating procedures is vital for company ops especially when you move to 2 crew. I have used flows checklists do lists and memonics throughout my career and personally think that well thought out flows supplemented by checklists are the way to go. But i'm happy to do whatever the company wants as told as long as there are wheels to land on and it's not safety critical.
As for instructors teaching rubbish well yes some don't know better but don't tell them they are wrong before a test wait till the paperwork is sent to CASA then explain with appropriate references to your cause. ps don't expect any popularity prizes for fault finding either there are some delicate egos
in aviation.