For the low end (low cost) paint jobs, you get what you pay for. It will be done with low quallity materials and will not be very durable. The bodywork prep will be minimal and it may look good at first, but it definitely will not last. Getting paint to match is difficult, but it can be done with excellent results. There are shops that can match colors and blend the panels, but it is not cheap for a quality job.
I use PPG products and my current project is a '67 Mustang which I am doing complete restoration. I have over $2000 invested in paint materials. PPG may be a bit more expensive than HOK and Dupont products, but it is a durable and established paint system.