There is no comparison between the larger flight schools vs flying clubs when it comes to professionalism.
Flying clubs let you fly in jeans, whereas the flight schools require your shirt to be ironed, shoes polished and you to present yourself in the same manner as you would to future employers.
I did my initial training at 43, but since then I have been involved with 5 or 6 other training organisations.
It does depend on your end goal.
I'll reiterate what I originally said, if you want to do a PPL only, don't do it at 43 or AIFA, or a large air school. Do it at a local flying club somewhere. Do it somewhere nice, somewhere scenic, and have fun while you do it.
If you want to pursue aviation as a profession, then go to a large Air School. They will make you fly when you don't feel like it, they will make you fly early mornings, late at night, they will make you fly when you would rather be in the pub. They won't hold your hand, and you will fly with many different instructors. At times you will feel like you are in a sausage factory, but at the end you will emerge a more professional pilot.
However, if all you want to do is a PPL, then find somewhere small, somewhere nice, that allows you to go at your own pace, somewhere with a core of old pilots who will tell you stories around the braai, somewhere that you will enjoy.