first question-do you need a zigzag stitch? if so, does the industrial machine have one. some do not.
The thing about a real industrial machine is that they are built to last, have no plastic gears and do not break down easily.
2nd question-does your neighbor have the manual? if not check the internet to see if you can buy it online. A good manual is critical. It will tell you how to use your machine, how to maintain it and what to do when something goes wrong.
If you are only doing straight sewing, an older mechanical machine would serve you best. They are easy to use, maintain and fix.
The older machines generally can sew through several layers of soft leather, 8 or 9 layers of heavy denim as well as silk and chiffon. The Key is the needle and the thread. Never use the cheap stuff found in the dollar store, and use the needle designed for the fabric. Schmedts and Organ are the 2 top needle makers and have needle specifically for denim and leather. A sewing machine manual usually will tell you which thread to use and what needle for each fabric.