As someone said, Macco's low end paint jobs use really low quality paint and is single stage, unless something has changed over the years.
They have a reputation of doing shoddy bodywork but that's all the franchise. Not to say you shouldn't do it yourself but that's not the reason why a Macco paintjob is bad, or not the only reason.
I know a very small number of people who have had an OEM quality job at Macco. Realize that each is different. The thing in common was that they did their own bodywork and sourced their own paint. It's not cheap and not going to be close to $650 or whatever they are charging now but can be cheaper than other shops. On the flipside, I know many more people who have gone to a lower end body shop and paid around $1500-2000 and had a good paint job, about what you would likely spend at Macco, including supplies, when all is said and done.