Sorry but not wise words at all. Total rubbish in fact. Visit the schools in question on this list. Count the aircraft. Count the (full time career) instructors. Look around the maintenance hangar(s). You will find the schools to be totally different in scale of operation, customer base and resources.
One of the schools on your list has been operating continuously from the same base for forty years. One of the others has only been operating for a few months.
If you are going to offer advice on this forum, why not do a little homework and research rather than just spout the first B****ks that comes off your keyboard.
Now don't be an idiot. Or anything like as rude. I suggest you apologise.
For a start, SF182 does have a point. Most schools are similar in many ways. I also wouldn't start spouting complete tripe about maintenance etc. I've worked for many different schools up here and I can tell you quite categorically that they are all just as sh*te as eachother. That includes the ones with their own maintenance facilities.
As for the long term financial survival of any flying school or club...You might as well throw a dice. Past performance has nothing to do with survival. In fact I'd rather go with a well funded startup company than a struggling established player any day of the week. Though I make no judgement on the finances of any school in Scotland.
The simple principle of choosing a school is this. Be cynical, visit them all, look past the shiny toppings, meet the instructors,
never pay up front and train where you feel most comfortable.
There is no "best" school. They all have positives and negatives.
Here are a few other things to think about when choosing your instructor and school. Stick with the same instuctor as much as possible, make sure your FI is not too wet behind the ears, make sure they are passionate about instructing and check their availability. What are the opening hours, how far are you needing to travel (don't choose a school that is more than an hour away, it'll just annoy the hell out of you) Look at the time they have available for each lesson (avoid weekends if possible), what other activities are there outside of just turning up to train?
That is where most flying schools fall down enormously, there is nothing much beyond getting you a PPL. Once you have that, what else is there? Can you do more advanced training, IMC, Aero's, Tailwheel? Fly more interesting aircraft? Etc.Etc.
Experience in an instructor is of course a good thing, though it is not the be all and end all. You need to get on with them too.
I don't want to be accused of being biased, so I won't make any specific school recommendations on here.
Just go up and have fun. Wherever allows you to do that the most, is the place to train. If you are happy, you'll learn better. It doesn't matter if you are flying a Cessna, Piper, Grob, Traumahawk (though how anyone can enjoy flying one of those pieces of cr*p I'll never know) the simple tenet is have fun.