Think more about the school than what is better, high or low wing. How is the school doing? Look at their equipment, (airplanes) are they well maintained, clean, tires in good shape, interiors? How about the school itself, is it clean, well lighted, has classroom(s)? Does this school look hungry, skimping on things to save money?
How about the instructors, how long have they been with the school?
Don't do what I did and get into a flying school that traded instructors every few weeks. My six to eight month and six to eight thousand dollar flying course turned into a never ending rotation of flight instructors, unsafe and filthy airplanes. Twenty four months after starting with them and numerous flight instructors later, I had still not left the pattern on my own.
My advise would be to join a flying club that has decent airplanes, then hire an instructor through that club. Make sure it is not a business, disguised as a flying club.
Sometimes you can find an instructor who will help you find a suitable airplane you can rent for your lessons, that would be the best way. How about training in a tri pacer?
If your a young fellow, you are probably going to do fine in a school. If your an older person, the school may consider you a cash cow and keep leading you on while insuring you go nowhere. That is what I experienced in a school, the older guys all had to go elsewhere to get their licenses.
If the school or it's equipment look dirty and shabby, go somewhere else. Most schools are desperate for cash and are hanging on for dear life. Be especially wary if the school wants a large chunk of cash up front, or is eager to help you arrange a loan for your lessons. You could very well find the school closed for good when you show up for a lesson, but you will still owe the money.
Please note: If you are the owner of a flying school and find this to be unsettling or unfair, in that I am penalizing all schools for the action of one, please consider this: If you don't want people bad mouthing your industry, how about policing your industry. Start a business association or join one. Set standards, do something about the state of most flying schools.
John