Egyptians choose new president amid political chaos NEW: "People who believed in parliament elections were let down," a Cairo resident says NEW: Some disgruntled voters unhappy with both candidates start campaign to invalidate ballots The election pits the Muslim Brotherhood's Mohamed Morsi against former Prime Minister Ahmed Shafik Cairo (CNN) -- Egyptians voted Saturday in the nation's first free presidential election, a runoff that pits a conservative Islamist against a former prime minister who served in the regime toppled last year. The election highlights the candidates' stark differences at the crux of the political turmoil gripping Egypt and for many voters, the two men presented a choice of lesser of two evils. On one side, Mohamed Morsi, an Islamist backed by the political arm of the Muslim Brotherhood. On the other, Ahmed Shafik, a former air force general and the last prime minister in Hosni Mubarak's regime. "I was planning to boycott the elections because I feel neither candidate represents the Egypt we wanted, but my family convinced me," said Yousef Hamad, a retired English professor in central Cairo. These next two days will shape Egypt's history. I am standing in the long line to vote for the more experienced candidate who will hopefully save Egypt's economy before it completely collapses. Hamad did not reveal his vote but another Cairo resident said Shafik was his choice. "The majority of our staff will be voting for Shafik," said Mohammed Ali, a hotel manager. We need security and we want to recover economically. Not because Shafik is a great option, but let's say he is the best of the worst. Still, others could not stomach a vote for a man who remains a symbol of the former regime of Hosni Mubarak, ousted in a popular uprising in February 2011. "I will be voting for Mohamed Morsi because the country needs real change," said Mohammed Zain, who lives in Egypt's second-largest city of Alexandria. "We deserve a new direction," he said. We have no problem if Shafik wins but we fear that this will lead to instability. The country doesn't need that. Without a parliament, a president will wield extraordinary power, dealing directly with the military rulers while a new constitution is written and until new parliamentary elections are held. "The people who believed in parliament elections were let down and their votes didn't mean anything, which angers me," said Ahmed Nassar, a Cairo graduate student. Some disgruntled voters unhappy with both candidates launched a campaign to invalidate ballots, according to Mohamed Ghoneim, the founder of the group. Members of the group marked X on both candidates' names on the ballot, nullifying the vote, he said. Voters are casting ballots Saturday and Sunday at a time when Egypt has neither a parliament nor a new constitution that defines the president's powers. A shocking court ruling Thursday dissolved parliament and raised serious questions on whether the powerful Supreme Council of the Armed Forces, Egypt's de facto rulers since Mubarak's ouster, will relinquish power. The biggest question facing 50 million Egyptians eligible to cast ballots in the runoff is what happens next. "I voted for Shafik because I don't want Egypt to become Iran," said Cairo taxi driver Taher Fathi, showing off his purple ink-stained finger as proof that he voted. The runoff follows a May election that failed to produce a winner with a clear majority. Polls were open for 12 hours starting at 8 a.m. both Saturday and Sunday. Votes must be counted by Monday, with final results scheduled to be announced by Thursday. Though anger festered over the court's ruling on the parliament, Cairo's streets remained relatively quiet compared with the popular demonstrations in February 2011. CNN's Saad Abedine, Ben Wedeman and Faith Karimi contributed to this report.