The three candidates competing to run the San Francisco assessor-recorder's office, which bills a hefty $1 billion in property taxes every year, agree on one thing: This race is about who is a professional and who is just a politician.

Each of the candidates running in the Nov. 8 election -- Ron Chun, Gerardo Sandoval and Philip Ting -- says he is the most competent, while the others are opportunists who will run for any vacant office.

They are fighting to win an administrative job that oversees the 179,000 properties that make up the city's biggest property tax roll ever. The revenue helps fund everything from playgrounds to police.

The next assessor-recorder takes over at a critical time. More than 1,800 commercial and residential property owners have asked the city to reassess their properties at lower values so they can pay less in taxes. Roughly $177 million in city revenue is at stake this year, and the assessor's job will be to defend it.

The candidates all say they have the right credentials.

Chun, a tax attorney, sat on the city's property assessment appeals board and worked in the assessor's office for six months. Sandoval, a two-term supervisor representing southside District 11, has a public track record at City Hall and a law degree. And Ting, appointed assessor by Mayor Gavin Newsom earlier this year, is running the office right now.

The professional vs. politician debate started with Newsom when he said he wanted to professionalize the office after Mabel Teng resigned in April. Teng, a former supervisor, stepped down after barely a year in office, during which she was accused of hiring and giving tax breaks to people with political and personal ties to her.

Before her, assessor Doris Ward had been caught skipping work and missing out on tax revenue in her decade on the job, which was punctuated by an FBI investigation into whether she used public funds for campaign purposes.

Newsom asked Chun, who ran for assessor in 2002, and Ting, who was planning a run for supervisor in the Sunset District, to interview for the job.

Ting's resume "matched the job description," Newsom said.

Ting's appointment surprised City Hall insiders who knew he was aligned with Matt Gonzalez, the former Board of Supervisors president who ran in the 2003 mayor's race against Newsom. Gonzalez appointed Ting to the Building Inspection Commission in 2004.

Ting's resume includes degrees from UC Berkeley and Harvard and a background in appraisals and multimillion-dollar real estate transactions. He most recently headed the Asian Law Caucus and did volunteer work on civil rights issues with Organization of Chinese Americans.

The mayor's stated rationale for appointing Ting became Ting's campaign slogan -- "A professional, not a politician." Endorsers include elected officials such as U.S. Sen. Dianne Feinstein and District Attorney Kamala Harris.

Ting's campaign team is managed closely by seasoned consultant Eric Jaye, who handled Newsom's mayoral run, even to the point of sitting in on candidate interviews with newspaper reporters.

Ting has been making regular announcements from his office about getting more money from billboard owners, granting tax relief to city residents whose personal property is destroyed in a natural disaster and working more closely with the building inspection department to ensure that property owners pay taxes on new construction in the city.

"If the office is poorly managed, that money (for city services) is not there," said Ting, 36, who owns a house in the Sunset District.

Sandoval, a former public defender who was first elected supervisor in 2000 and will be forced out by term limits in 2008, said a lawyer needs to run and protect the office because so many big property owners are fighting for lower assessments right now.

"There is $100 million in revenue the city could lose if we don't have an assessor who fights just as hard as the people making the appeals fight," Sandoval said.

He said he has the professional and experience edge after earning a law degree from Columbia and a master's degree in city planning from UC Berkeley. He has worked as a financial analyst for Mayors Art Agnos and Frank Jordan, a transportation commissioner overseeing Muni and a lawyer in the public defender's office for five years.

His plans for the assessor's office include creating a special team to handle assessment appeals, creating another team to answer public inquiries, put all public records online and finish updating computer systems.

Sandoval, 43, owns a home in the Excelsior district.

Chun, 46, is a tax attorney who says he has the most experience working in the assessor's office.

"We need a professional in that office. The other two candidates neither have experience or qualifications that I do," Chun said.

While working in the assessor's office in 2002, he helped Ward in her efforts to end the practice of reassessing a gay couple's shared property after one partner dies. Under state law, only married couples are exempted from having their property reassessed when a spouse dies.

His plans for the office include improving staff morale by hiring more workers, he said. And the computer system needs an upgrade so deeds and other documents can be filled out using a Web-based program, he said.

Chun began his campaign with television spots that mock "King Gavin's" choice for assessor.

For such a low-profile office, the campaign attacks have been unusually early and fierce.

Chun, who moved his family to Palo Alto, has been accused of not really living in San Francisco, even though he rented an apartment here.

Sandoval fought accusations of misuse of campaign funds after putting his wife on the payroll of his last campaign for supervisor.

And Ting's claims that he's not a politician came under fire. His opponents pointed out that Ting ran or expressed interest in running for two other political offices -- supervisor and a municipal utility district board member -- in recent years.

Sandoval and Chun also accused Ting of illegally sending a fundraising mailer on supporter District Attorney Harris' stationery and violating city ethics laws.

The races for assessor and for city treasurer next month will be the first citywide offices to be decided by ranked-choice voting, which eliminates the need for a runoff election in December.

Voters get to rank candidates in each race in order of preference. If no candidate wins more than 50 percent of the vote on the initial count, the bottom candidate drops out and his or her votes are redistributed to second-choice candidates. The process continues until one candidate gains a majority.

The San Francisco League of Women Voters will hold an assessor-recorder candidate forum at 7 p.m. Oct. 20 at the Charles M. Holmes LGBT Center, 1800 Market St