I'm a big fan of Griots, Bilt Hamber and the final one would probably be between Meguiars or Adams.
CarPro has many great products but they're a bit pricey here.
I'd recommend investing a lot of time and maybe even money into learning it before even thinking about doing a clients car, however, PDR is both relevant and can be very lucrative.
It's not for everyone though, it's a very tedious process.