Found a great PDF that breaks it down in plain English.

Here's a quote for consideration:

"Advocates like to assert that sales taxes are pro-family relative to the income tax. But
children and families benefit disproportionately from numerous features of the current system,
including dependent exemptions, child credits, child care credits, earned income credits and
education credits. And the preferential treatment of housing, health insurance, and state and local
tax payments also plausibly helps families, since they consume relatively more housing, medical
services, and government-provided services such as education. All of these preferences would be
eliminated under a sales tax. Moreover, compared to childless couples, families with kids generally
have high consumption relative to income, so switching from income tax to a consumption tax
would further raise tax burdens during years when family needs were highest. Based on 1996 data,
a recent study found that enactment of a broad-based, flat-rate consumption tax like the sales tax or
flat tax would hurt families with incomes less than $200,000, because of the loss of tax preferences,
but would help families with income above $200,000, due to the dramatic reduction in the top tax
rate. Incorporating the 1997 and 2001 tax changes—especially the child and education credits-—
would only exacerbate these results."