Nixon, a Democrat, points out that since his first year in office the state's unemployment rate has been below the national average. In August, the state added 17,900 jobs, third most in the nation. And agricultural exports continue to rise, up 32 percent in 2010 and 17 percent last year.
"When I started there were some economic challenges the entire nation and the state were facing," Nixon said. "We focused on those early, and we're making real progress."
Spence counters with his own numbers that paint a much bleaker picture: One in six Missourians is on food stamps. More than 100,000 have quit looking for work since Nixon took office. Median household income fell 3.2 percent last year to $45,774 -- the lowest figure since 1994.
"Is this truly the best we can do? Is this our legacy we're leaving to our kids and grandkids?" Spence asked.
With the economy and jobs at the forefront of many voters' minds, which version Missourians believe will go a long way in determining the state's next governor on Nov. 6.
So far, polls have consistently shown Nixon with a large lead. But even though most agree the race is Nixon's to lose, the Democratic incumbent faces an electorate that has been trending Republican for more than a decade.
Nixon, however, is busy touting his accomplishments, especially "bringing people together from both parties to balance the budget, maintaining our state's AAA bond rating and holding the line on taxes."
Nixon, who served as attorney general for 16 years before becoming governor in 2009, also points to his decision to call lawmakers into a special session in 2009 to pass an economic incentives package aimed at the automobile industry.
Last year, Ford Motor Co. announced a plan to invest $1.1 billion in its facility near Kansas City. General Motors broke ground in Wentzville outside St. Louis for a $380 million expansion project in May.
"We're witnessing the rebirth of America's automotive industry right here in Missouri," Nixon said.
Nixon's last two years as governor have coincided with historically large Republican majorities in the Missouri House and Senate. So while the governor can brag about working across the aisle, he also lists among his accomplishments several bills he vetoed -- most prominently one mandating voters show ID to cast a ballot, and another making it more difficult to prove discrimination cases against former employers.
"I've been working with the legislature that is controlled by the other party, and we've gotten stuff done," he said. "We haven't had any budget meltdowns or government shutdowns."
But Spence, the former CEO of a St. Louis-based plastics company who has never run for office, maintains that the governor's vetoes have hurt Missouri's economy. The workplace discrimination bill, for example, would simply make state law mirror the federal Civil Rights Act, he said.
"We're now called the Sue-Me State, not the Show-Me State," he added. "It's time to change that."
The bill has been a major legislative priority for the Missouri Chamber of Commerce and Industry for several years. Spence has received the organization's endorsement and has adopted much of the Chamber's legislative agenda.
In addition to the workplace discrimination bill, Spence supports overhauling the state's workers compensation system, reinstating caps on medical malpractice awards and passing a "right-to-work" law that would ban the requirement for workers to pay union dues as a condition of employment.
One thing Spence insisted won't be on his agenda right away are tax cuts.
"I think it would be great to cut taxes, but we are barely paying our bills right now," he said. "If given a choice, people would rather pay fewer taxes, but I don't think we can afford tax cuts right now."
Both candidates favor overhauling the state's tax credit system. Nixon said tax credit programs cost the state $627 million last year, fully one-twelfth of the state budget. While he said he supports many of these programs, he noted that "we have to bend that cost curve ... I'm hopeful about getting that done."
Spence said he would push to cap all tax credit programs and would end those that don't produce a return on investment for the state. In fact, he would take a similar approach to everything government does.
"It's time we lift up every rock, see how we do things, and see if we can do it any better or whether we should be doing it at all," Spence said. "That's the fresh eyes and fresh perspective I bring to this race."
One of those areas could be education. For three straight years, Missouri's public colleges and universities have seen their funding cut. The latest came in June, when Nixon announced $9 million in reductions. When combined with previous cuts, higher education funding has fallen about $120 million since the 2009-2010 school year.
Spence has criticized Nixon's decision to cut higher education funding, arguing that it amounted to "cutting your sales force when sales were down. It just doesn't make sense."
By implementing policies that help businesses grow, Spence believes employment will increase and more Missourians will be paying taxes.
"If we get more taxpayers, we'll have more funding and we can adequately fund our education system," he said.
Nixon counters that making college more accessible and more affordable has been a major focus of his administration. He has expanded the A-plus program that provides scholarships for two years of community college for qualified students, and has worked to get strategic funding into higher education, such as $9 million in grants to establish "Innovation Campuses" throughout Missouri.
He also pointed out that, despite three years of funding cuts, tuition increases at public four year institutions in the state were the lowest in the country over the last three years.
Yet, with three weeks to go before Election Day, Nixon's campaign has trained its focus on Spence's role at a bank that received a federal bailout.
In a series of state-wide television ads, the Democrat painted a picture of Spence as a "St. Louis banker" who accepted a bailout, but "refused to pay back the taxpayers." Instead, the ad accuses Spence of taking "an insider loan to buy a million dollar vacation home."
Spence has called the ads "false" and "defamatory," and asked television stations to stop running them. Last week he filed a defamation lawsuit against Nixon, saying the governor maliciously broadcast false statements about Spence's role with a bank.
Oren Shur, Nixon's campaign manager, called the lawsuit "misguided and desperate."
"The stress of the campaign is clearly taking a toll on Dave Spence, but he should take a deep breath, and consider honestly defending his record at the bank instead of having his campaign manager file a frivolous lawsuit," he said.
Spence joined the board of Reliance Bank in May 2005. The decision to take a $40 million loan under the Troubled Asset Relief Program was made by the board of the bank's holding company, Reliance Bancshares. Spence did eventually join the holding company's board, but not until two months after the decision to accept TARP funds was already made.
In 2010, he took out a $1.1 million mortgage on a vacation home at the Lake of the Ozarks. Before resigning from the board in March 2011, Spence voted with the rest of the board to stop paying back the TARP loan.
Before filing the lawsuit, Spence told a group of supporters in Springfield that Nixon's ad campaign demonstrates that the governor has "sold his soul to the devil" in order to get re-elected.
"If he's willing to trash my reputation to get re-elected when he knows that's not the truth ... that to me is selling your soul to the devil," Spence told The Associated Press.
Nixon's campaign responded to that statement by instructing Spence to "pull himself together and get a grip."