Two big-spending candidates trumpeting their reform credentials are vying in Miami-Dade's closely contested mayoral runoff election, but have voters just tuned them out?

Julio Robaina and Carlos Gimenez are fighting down to the wire. Robaina, the mayor of Hialeah, edged Gimenez, a county commissioner, in the initial round of voting and he maintains a sizable fundraising lead, as well as the backing of the influential Latin Builders Association.

But questions continue to swirl around Robaina, and polls sponsored by local media, which have endorsed Gimenez, show the commissioner with a lead heading into Election Day Tuesday.

"Gimenez has gained steam and Robaina has received a lot of negative publicity," says Sean Foreman, a political science professor at Barry University in Miami Shores.

Reportedly the target of two federal investigations into his financial and political dealings, Robaina tried to seize the initiative last week when he unveiled an economic plan for deficit-plagued Miami-Dade County.

Contrasting himself against former county Mayor Carlos Alvarez, who was ousted in a recall election earlier this year, Robaina declared:

"If we do not take immediate steps to scale back the county’s $7.3 billion budget and revoke the property tax increases of 2010, we will not be able to give our residents, business owners and new investors the confidence to know that Miami-Dade government is headed in the right direction."

Robaina's plan calls for halving the county's current 60-plus departments and repealing what he calls "unjustifiable salary increases." He also proposes that union contracts be scrutinized for cost savings while building incentive-based compensation.

While the Robaina campaign fosters the perception of the mayor as a businessman and Gimenez as a lifelong politician and bureaucrat, Foreman, who has moderated mayoral forums, says, "Both guys are very knowledgeable on county issues and both are connected to the power structure.

"It seems that each would be able to hit the ground running and they will have to act quickly because a budget is due within weeks of entering office and there could be a shortfall of up to $400 million."

Still, J.C. Flores, Gimenez's campaign manager, questioned Robaina's credibility on fiscal matters.

“We should all be wary of any economic plan Mr. Robaina proposes, given that Hialeah suffers from an unemployment rate of 17.3 percent due to his mismanagement as mayor," Flores said.

Flores went on to accuse Robaina of "awarding excessive salaries to his top associates and dramatically increasing his own office budget by 18 percent, all while enjoying the highest salary of any mayor in the state."

Additionally, Flores pounded Robaina for supporting the county's costly and controversial Marlins stadium deal, which Gimenez opposed.

Norman Braman, the South Florida auto magnate who engineered the successful recall of Alvarez, hasn't taken sides in the runoff. That has allowed both Robaina and Gimenez to claim bragging rights as reformers.

So the runoff between the two Republicans could swing on social and ethnic lines.

Luther Campbell, a former rapper with high visibility in Miami's African-American community, endorsed Robaina after earlier speculation put him in the Gimenez camp. Campbell received 11 percent of the vote in the first round.

But Gimenez received the backing of former state Rep. Marcel Llorente, who finished third in the initial round.

"While Robaina's base is solid in Hialeah and among working-class Hispanics, a recent poll shows that Gimenez has gained strength among all ethnic groups with more support from Anglos, African-Americans and Hispanics as a whole," Foreman said.