I can't comment personally on Maaco, but I've used Earl Scheib (sp?) once and know a few others who have used them also. I've also talked with several people here and there who have done business with one of these companies. Maaco and Scheib share the same business model, and they've both been around for a while, so I suspect they are very comparable.
I can only say this: you are NOT going to get an $1800 paint job for $199. Duh, as if I had to say that. On the other hand, if all you want them to do is shoot the color and clear coat - nothing more - and you are willing to do most if not ALL the prep yourself, you can't beat the $200 - $300 deals.
If you leave them to do the prep, they do as little as they can possibly get away with. I've seen lots of defects directly attributable to poor surface prep.
Before Sheib's painted my car, I took all the moldings, emblems, mirrors, bezels, and trim off the car myself. A friend and I knocked the finish down at least one layer of base (it was being painted the same color). We did most of the masking, leaving a few things for Sheibs (we wrote down what needed to be done), then we had it towed to the paint shop (an extra $70). There were no defects in the body like as dents or rust, at least none that I couldn't live with.
All Sheib's had to do was finish masking a few things, give the car a final wipe-down, then shoot. It turned out great, there were no defects that a little wet-sanding and polishing would not cure. The paint job was better than it left the factory with and certainly lasted longer. The car was an '87 Olds Cutlass that was made when GM was phasing in clear-coat only on certain models. Except, GM used a base coat on the car but they didn't clear-coat it! By the time I bought the car in 1992, the finish looked 20 years old.