Preference shares are shares that have preferential rights to dividends and repayment of capital compared to common shares. There are several types of preference shares: cumulative vs non-cumulative, participating vs non-participating, convertible vs non-convertible, and redeemable vs non-redeemable. Preference shares provide benefits like helping companies raise long-term capital and guaranteeing fixed returns, but also have drawbacks like lack of trading and lower returns.