In theory, the VAT, FairTax, and Flat Tax create an equal burden on the consumer, if the tax rates are equal. In practice, gross salaries would have to be reduced to get rid of the embedded income taxes, if you were to switch. Since that will not happen, conversion will create a one-time inflation-like increase in prices of approximately 25%, if we got rid of the income tax and moved to a FairTax. (See the footnote on page 144 of "FairTax: The Truth" -- 'prices would rise by 24.8% but wages would rise by 27.4%')
Because of the tax accommodation embedded in gross salaries , switching to either VAT or FairTax is fatally flawed, so we need a Progressive Flat Tax - see my comment above.