The quality is normally below industry standards. When you compare the cost and quality to that of a reputable company that will not hire illegals you will find you are saving money with the more reputable company. Here are a few ways people will skimp on quality.
*POOR SURFACE PREPARATION
*APPLYING LESS MATERIAL THAN THE PRODUCT SPECIFIES
Two other things come to mind when speaking of illegal workers, NO INSURANCE ( what if there is a worksite injury?), PRODUCT FAILURES ( who will you call, will they come back?).
It is not that these are bad people, but there are reasons they are cheeper, and in the long run it will cost you money!!