Party unity, economic stability and an election victory over the three-term Liberal government are the biggest of the many promises being tossed around the B.C. New Democratic Party leadership race.

Almost 30,000 NDP members will decide Sunday who becomes the next party leader from among the four candidates running to succeed Carole James, who quit last December during a vicious public feud over her leadership.

"You're not just choosing the next leader of the official Opposition," said leadership candidate Mike Farnworth, when he announced his bid at community centre in his Port Coquitlam-area riding.

"Let's be clear: you are choosing the next premier of the province after we defeat the Liberal government," said Farnworth, a long-time New Democrat MLA who held cabinet posts in the Glen Clark NDP government of the mid-1990s.

His leadership rival, Adrian Dix stood inside the auditorium of an elementary school in his Vancouver-Kingsway riding and promised leadership that brings results and victory.

"The New Democratic Party has to make a choice -- who will lead it into the next provincial election?" said Dix, a former backroom New Democrat who worked closely with Clark and now holds the former premier's riding.

"Who can best defeat the BC Liberals? Most importantly, who can lead British Columbia into a more progressive future?"

Dix said he's up to the task.

"I have the energy required to lead the party and to lead the party to victory and to be premier of British Columbia," he said.

John Horgan joined the race promising a commonsense alternative to the Liberals, taking his engaging personal style to kitchens, living rooms and community halls throughout the province to convince British Columbians that they're New Democrats at heart.

"(People) want an NDP that sets out a positive vision and excites British Columbians about our ideas," said Horgan, also a former backroom New Democrat who worked in Ottawa and in Victoria as former Premier Dan Miller's chief of staff.

"It's time to pull together as New Democrats and take the fight to the BC Liberals.

"Under my leadership, the NDP will present voters with a credible, pragmatic alternative to a government that has ignored the needs and interests of British Columbians for far too long."

Long-shot candidate Dana Larsen, who was forced to drop out of the 2008 federal campaign as an NDP candidate after images surfaced on the Internet of him smoking marijuana and talking about drugs, chose his Vancouver medical marijuana dispensing office to launch his campaign. He promised to grow the party's socialist roots, with a focus on social justice and crime, and, of course, loosening marijuana laws.

Norman Ruff, a retired professor of political science from the University of Victoria, said each candidate has attempted to put a positive spin on the two NDP governments of the 1990s, whose terms were marred by scandal and economic decline.

And while the three front-running leadership candidates may have run similar campaigns when it comes to social issues such as poverty and homelessness, he said they differ on tax policies.

Dix wants to review and rollback tax breaks for corporations, Horgan wants to establish a tax review commission, while Farnworth wants to wait until the province decides what to do with the harmonized sales tax. British Columbians start voting in June in a referendum on the future of the HST, the 12-per cent combined federal Goods and Services Tax and the former provincial sales tax.

"They are all very similar but the tax question is where you start to see the differences," he said. "Their position on tax reflects their overall style."

Dix, with his promise to bring corporate taxes back to 2008 levels, shows his willingness to engage the business community, while Horgan's tax commission shows his pragmatic side. Farnworth's HST delay reveals a sense of caution during potentially stormy times, Ruff said.

Farnworth promises a royal commission to ensure the province has a comprehensive vision for education, and he promises to use money from the B.C. carbon tax to improve public transit and stimulate green initiatives.

Farnworth also committed to legislated poverty reduction targets and appointment of a minister responsible for poverty reduction.

Dix promises to dump the HST and "rebalance corporate taxes."

He said he would use carbon tax revenues to fund public transit, would charge fees and taxes in an effort to restrict raw log exports and will encourage B.C.'s health-care system to buy locally grown produce.

But public education and health care will be his top priorities, he said, while Horgan said economic growth and social justice would be the hallmarks of his leadership.

Horgan also promises to shut down the government's money-making online casino.