Need help/advice..

I live in Florida and own a 10 year old (Ameristar 3 ton) heat pump that’s on its last leg. Still works but its working at lower efficiency and the compressor is humming during use. I know a contractor than can get me a 3 ton Rheem unit installed for 7.5k. Its a reputable business and they’ve been around for a while. On the other hand, i know a family friend who will install a Trane unit for the same price. My concern is he’s kind of works off the grid. He did my in-laws house and things seems to be working fine but not sure what kind of quality i’d be getting, or if he even pulls a permit for the work he does.

Any thoughts or suggestions are much appreciated. FYI the current unit sucks. It was installed when i bought the house and had no say in it.