It's not just the prep work. I believe they use single stage paint (like Maaco).
But, some people can't tell the difference between single stage and base coat/clear coat. Also, depends on the shop. I've seen some pretty decent single stage jobs and I've also seen some that look like it was sprayed with a rattle can.
Best thing for you to do is go down to the shop for yourself and see the work that they're putting out and if it'll satisfy your needs.
