Presidential candidate Herman Cain's 999 Plan is part of what's propelled him to the front of the GOP field. But it is drawing criticism from economists. 

The plan would replace the current complicated income tax system, but it would also kill tax deductions that many Americans and businesses like.

"Nine percent corporate business flat tax, 9 percent personal income flat tax, and a 9 percent national sales tax," Cain explained.
    
While his plan seems to be resonating with voters, many economists are skeptical.

"It's going to raise the price of just about everything by about 9 percent," said Bruce Bartlett, a former Treasury official under President George H.W. Bush.

William McBride, an economist with the Tax Foundation, was more optimistic.

"Relative to the current system, it is a big improvement," he said. "999 is fundamentally scrapping the tax code and starting over, and there is very good reason to do that."

Some conservatives don't like Cain's idea of a national sales tax.

"Turn it upside down. I think the devil's in the details."  Rep. Michele Bachmann, R-Minn., said of the 999 Plan during Tuesday's GOP presidential debate.

In the meantime, everyone is watching and waiting to see if the former Godfather Pizza CEO will hang on and prove he's more than just the current fad.

"There's a difference between the flavor of the week and Haagen Daaz black walnut because it tastes good all the time," Cain said.